Read GITHUB_TOKEN if JEKYLL_GITHUB_TOKEN does not exist; document this

CONTRIBUTING.md

@@ -73,10 +73,7 @@ hyperfine --warmup 2 "gojekyll build -s ${SITE_SRC}"
 ```
 
 If you run into an error after a few runs, add the `--show-ouput` option to
-`hyperfine`. If the error is "403 API rate limit exceeded", you are probably
+`hyperfine`.
-building a repository that uses the `jekyll-github-metadata` gem; try setting
-the `JEKYLL_GITHUB_TOKEN` environment variable to the value of a GitHub access
-token and trying again.
 
 ### Coverage
 

README.md

@@ -15,7 +15,7 @@ language. It provides `build` and `serve` commands, with directory watch and
 live reload.
 
 |                    | Gojekyll                                  | Jekyll | Hugo                         |
-|-------------------------|-------------------------------------------|--------|--------------|
+| ----------------------- | ----------------------------------------- | ------ | ---------------------------- |
 | Stable                  |                                           | ✓      | ✓                            |
 | Fast                    | ✓<br>([~20×Jekyll](./docs/benchmarks.md)) |        | ✓                            |
 | Template language       | Liquid                                    | Liquid | Go, Ace and Amber templates  |
@@ -27,7 +27,6 @@ live reload.
 
 <!-- TOC -->
 
-- [Gojekyll](#gojekyll)
 - [Usage](#usage)
 - [Installation](#installation)
   - [Binary Downloads](#binary-downloads)
@@ -37,6 +36,7 @@ live reload.
   - [Current Limitations](#current-limitations)
   - [Other Differences](#other-differences)
   - [Feature Checklist](#feature-checklist)
+- [Troubleshooting](#troubleshooting)
 - [Contributors](#contributors)
 - [Attribution](#attribution)
 - [Related](#related)
@@ -194,6 +194,16 @@ Muzukashii:
   - [ ] `doctor`, `import`, `new`, `new-theme` – not planned
 - [ ] Windows
 
+## Troubleshooting
+
+If the error is "403 API rate limit exceeded", you are probably building a
+repository that uses the `jekyll-github-metadata` gem. Try setting the
+`JEKYLL_GITHUB_TOKEN`, `JEKYLL_GITHUB_TOKEN`, or `OCTOKIT_ACCESS_TOKEN`
+environment variable to the value of a [GitHub personal access
+token][personal-access-token] and trying again.
+
+[personal-access-token]: https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/creating-a-personal-access-token
+
 ## Contributors
 
 Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/docs/en/emoji-key)):
@@ -223,7 +233,7 @@ specification. [Contributions of any kind welcome](./CONTRIBUTING.md)!
 Gojekyll uses these libraries:
 
 | Package                                                                        | Author(s)                                              | Usage                                  | License                                 |
-|--------------------------------------------------------------------------------|--------------------------------------------------------|----------------------------------------|-----------------------------------------|
+| ------------------------------------------------------------------------------ | ------------------------------------------------------ | -------------------------------------- | --------------------------------------- |
 | [github.com/jaschaephraim/lrserver](https://github.com/jaschaephraim/lrserver) | Jascha Ephraim                                         | Live Reload                            | MIT License                             |
 | [github.com/kyokomi/emoji](https://github.com/kyokomi/emoji)                   | kyokomi                                                | `jemoji` plugin emulation              | MIT License                             |
 | [github.com/osteele/liquid](https://github.com/osteele/liquid)                 | yours truly                                            | Liquid processor                       | MIT License                             |
@@ -240,7 +250,7 @@ In addition, the following pieces of text were taken from Jekyll and its plugins
 They are used under the terms of the MIT License.
 
 | Source                                                                          | Use                  | Description            |
-|---------------------------------------------------------------------------------|----------------------|------------------------|
+| ------------------------------------------------------------------------------- | -------------------- | ---------------------- |
 | [Jekyll template documentation](https://jekyllrb.com/docs/templates/)           | test cases           | filter examples        |
 | `jekyll help` command                                                           | `gojekyll help` text | help text              |
 | [`jekyll-feed` plugin](https://github.com/jekyll/jekyll-feed)                   | plugin emulation     | `feed.xml` template    |

plugins/github_metadata.go

@@ -88,6 +88,8 @@ func getGitHubRepo(nwo string) (*github.Repository, error) {
 	var ts oauth2.TokenSource
 	if tok := os.Getenv("JEKYLL_GITHUB_TOKEN"); tok != "" {
 		ts = oauth2.StaticTokenSource(&oauth2.Token{AccessToken: tok})
+	} else if tok := os.Getenv("GITHUB_TOKEN"); tok != "" {
+		ts = oauth2.StaticTokenSource(&oauth2.Token{AccessToken: tok})
 	} else if tok := os.Getenv("OCTOKIT_ACCESS_TOKEN"); tok != "" {
 		ts = oauth2.StaticTokenSource(&oauth2.Token{AccessToken: tok})
 	}