fix: Specify correct branch names in CI and PR workflows

1. pull request events are "funny", so we need to check out using `github.event.pull_request.head.ref` if the workflow step will commit anything. See actions/checkout#317 (comment)
2. Regular push events just check out the regular branch, but if this is enabled on multiple branches we need the ability to get the branch name dynamically. Use the new `GITHUB_REF_NAME` variable.

.github/workflows/ci.yml

@@ -140,7 +140,7 @@ jobs:
           githubToken: ${{ secrets.GH_TOKEN }}
           excludeCommit: ${{ github.event.head_commit.message }}
           forgeboxToken: ${{ secrets.FORGEBOX_TOKEN }}
-          branch: master
+          branch: ${ GITHUB_REF_NAME }
           plugins: '{ "VerifyConditions": "GitHubActionsConditionsVerifier@commandbox-semantic-release", "FetchLastRelease": "ForgeBoxReleaseFetcher@commandbox-semantic-release", "RetrieveCommits": "JGitCommitsRetriever@commandbox-semantic-release", "ParseCommit": "EmojiLogCommitParser@commandbox-semantic-release", "FilterCommits": "DefaultCommitFilterer@commandbox-semantic-release", "AnalyzeCommits": "DefaultCommitAnalyzer@commandbox-semantic-release", "VerifyRelease": "NullReleaseVerifier@commandbox-semantic-release", "GenerateNotes": "GitHubMarkdownNotesGenerator@commandbox-semantic-release", "UpdateChangelog": "FileAppendChangelogUpdater@commandbox-semantic-release", "CommitArtifacts": "GitHubArtifactsCommitter@commandbox-semantic-release", "PublishRelease": "ForgeBoxReleasePublisher@commandbox-semantic-release", "PublicizeRelease": "GitHubReleasePublicizer@commandbox-semantic-release" }'
 
       - name: Inform Slack

.github/workflows/pr.yml

@@ -96,7 +96,7 @@ jobs:
       - name: Checkout Repository
         uses: actions/checkout@v2
         with:
-          ref: ${{ github.head_ref }}
+          ref: ${{ github.event.pull_request.head.ref }}
 
       - uses: Ortus-Solutions/commandbox-action@v1
         with: