Add xml.xsd locally to prevent network issues

config.xsd

@@ -5,7 +5,7 @@
     targetNamespace="https://getpsalm.org/schema/config"
     elementFormDefault="qualified"
 >
-    <xs:import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="http://www.w3.org/2001/03/xml.xsd" />
+    <xs:import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="xml.xsd" />
     <xs:element name="psalm" type="PsalmType" />
 
     <xs:complexType name="PsalmType">

xml.xsd

@@ -0,0 +1,118 @@
+
+<?xml version='1.0'?>
+<!DOCTYPE xs:schema PUBLIC "-//W3C//DTD XMLSCHEMA 200102//EN" "XMLSchema.dtd" >
+<xs:schema targetNamespace="http://www.w3.org/XML/1998/namespace" xmlns:xs="http://www.w3.org/2001/XMLSchema" xml:lang="en">
+
+    <xs:annotation>
+        <xs:documentation>
+            See http://www.w3.org/XML/1998/namespace.html and
+            http://www.w3.org/TR/REC-xml for information about this namespace.
+
+            This schema document describes the XML namespace, in a form
+            suitable for import by other schema documents.
+
+            Note that local names in this namespace are intended to be defined
+            only by the World Wide Web Consortium or its subgroups.  The
+            following names are currently defined in this namespace and should
+            not be used with conflicting semantics by any Working Group,
+            specification, or document instance:
+
+            base (as an attribute name): denotes an attribute whose value
+            provides a URI to be used as the base for interpreting any
+            relative URIs in the scope of the element on which it
+            appears; its value is inherited.  This name is reserved
+            by virtue of its definition in the XML Base specification.
+
+            lang (as an attribute name): denotes an attribute whose value
+            is a language code for the natural language of the content of
+            any element; its value is inherited.  This name is reserved
+            by virtue of its definition in the XML specification.
+
+            space (as an attribute name): denotes an attribute whose
+            value is a keyword indicating what whitespace processing
+            discipline is intended for the content of the element; its
+            value is inherited.  This name is reserved by virtue of its
+            definition in the XML specification.
+
+            Father (in any context at all): denotes Jon Bosak, the chair of
+            the original XML Working Group.  This name is reserved by
+            the following decision of the W3C XML Plenary and
+            XML Coordination groups:
+
+            In appreciation for his vision, leadership and dedication
+            the W3C XML Plenary on this 10th day of February, 2000
+            reserves for Jon Bosak in perpetuity the XML name
+            xml:Father
+        </xs:documentation>
+    </xs:annotation>
+
+    <xs:annotation>
+        <xs:documentation>This schema defines attributes and an attribute group
+            suitable for use by
+            schemas wishing to allow xml:base, xml:lang or xml:space attributes
+            on elements they define.
+
+            To enable this, such a schema must import this schema
+            for the XML namespace, e.g. as follows:
+            &lt;schema . . .>
+            . . .
+            &lt;import namespace="http://www.w3.org/XML/1998/namespace"
+            schemaLocation="http://www.w3.org/2001/03/xml.xsd"/>
+
+            Subsequently, qualified reference to any of the attributes
+            or the group defined below will have the desired effect, e.g.
+
+            &lt;type . . .>
+            . . .
+            &lt;attributeGroup ref="xml:specialAttrs"/>
+
+            will define a type which will schema-validate an instance
+            element with any of those attributes</xs:documentation>
+    </xs:annotation>
+
+    <xs:annotation>
+        <xs:documentation>In keeping with the XML Schema WG's standard versioning
+            policy, this schema document will persist at
+            http://www.w3.org/2001/03/xml.xsd.
+            At the date of issue it can also be found at
+            http://www.w3.org/2001/xml.xsd.
+            The schema document at that URI may however change in the future,
+            in order to remain compatible with the latest version of XML Schema
+            itself.  In other words, if the XML Schema namespace changes, the version
+            of this document at
+            http://www.w3.org/2001/xml.xsd will change
+            accordingly; the version at
+            http://www.w3.org/2001/03/xml.xsd will not change.
+        </xs:documentation>
+    </xs:annotation>
+
+    <xs:attribute name="lang" type="xs:language">
+        <xs:annotation>
+            <xs:documentation>In due course, we should install the relevant ISO 2- and 3-letter
+                codes as the enumerated possible values . . .</xs:documentation>
+        </xs:annotation>
+    </xs:attribute>
+
+    <xs:attribute name="space" default="preserve">
+        <xs:simpleType>
+            <xs:restriction base="xs:NCName">
+                <xs:enumeration value="default"/>
+                <xs:enumeration value="preserve"/>
+            </xs:restriction>
+        </xs:simpleType>
+    </xs:attribute>
+
+    <xs:attribute name="base" type="xs:anyURI">
+        <xs:annotation>
+            <xs:documentation>See http://www.w3.org/TR/xmlbase/ for
+                information about this attribute.</xs:documentation>
+        </xs:annotation>
+    </xs:attribute>
+
+    <xs:attributeGroup name="specialAttrs">
+        <xs:attribute ref="xml:base"/>
+        <xs:attribute ref="xml:lang"/>
+        <xs:attribute ref="xml:space"/>
+    </xs:attributeGroup>
+
+</xs:schema>