actions: add context example

actions/example-pull-request/.forgejo/workflows/test.yml

@@ -33,6 +33,24 @@ jobs:
             echo value=true >> $GITHUB_OUTPUT
           fi
 
+      # See also actions/example-context/.forgejo/workflows/test.yml
+      - name: env.GITHUB_BASE_REF
+        run: |
+          set -x
+          test "$GITHUB_BASE_REF" = main
+          test "$GITHUB_BASE_REF" = "${{ env.GITHUB_BASE_REF }}"
+
+      # See also actions/example-context/.forgejo/workflows/test.yml
+      - name: env.GITHUB_HEAD_REF
+        run: |
+          set -x
+          if ${{ steps.forked.outputs.value }} ; then
+              test "$GITHUB_HEAD_REF" = main
+          else
+              test "$GITHUB_HEAD_REF" = other
+          fi
+          test "$GITHUB_HEAD_REF" = "${{ env.GITHUB_HEAD_REF }}"
+
       - name: secrets
         shell: bash
         run: |