Support GITHUB_TOKEN (#79)

Author: sethvargo

.github/workflows/test.yml

@@ -24,7 +24,5 @@ jobs:
           go-version: '1.21'
 
       - name: 'Run tests'
-        env:
-          ACTIONS_TOKEN: '${{ github.token }}'
         run: |-
           go test -count=1 -shuffle=on -timeout=10m -race ./...

README.md

@@ -213,7 +213,7 @@ function ratchet {
     system auth, similar to the Docker and gcloud CLIs.
 
 -   The GitHub resolver defaults to public github.com. Provide an oauth access
-    token with appropriate permissions via the `ACTIONS_TOKEN` environment
+    token with appropriate permissions via the `GITHUB_TOKEN` environment
     variable. To use a GitHub Enterprise installation, set the
     `ACTIONS_BASE_URL` and `ACTIONS_UPLOAD_URL` environment variables to point
     your instance.

resolver/actions.go

@@ -14,7 +14,7 @@ import (
 
 var (
 	ActionsBaseURL   = os.Getenv("ACTIONS_BASE_URL")
-	ActionsToken     = os.Getenv("ACTIONS_TOKEN")
+	ActionsToken     = coalesce(os.Getenv("ACTIONS_TOKEN"), os.Getenv("GITHUB_TOKEN"))
 	ActionsUploadURL = os.Getenv("ACTIONS_UPLOAD_URL")
 )
 
@@ -153,3 +153,12 @@ type GitHubRef struct {
 	path  string
 	ref   string
 }
+
+func coalesce(s ...string) string {
+	for _, v := range s {
+		if v != "" {
+			return v
+		}
+	}
+	return ""
+}