Also update floating tags on release (#44)

GitHub changed the immutable actions program, and it no longer computes
floating tags.

Author: sethvargo

.github/workflows/release.yml

@@ -47,6 +47,46 @@ jobs:
             --repo "${REPO}" \
             --draft=false
 
+  update-floating-tag:
+    runs-on: 'ubuntu-latest'
+    needs:
+      - 'create-release'
+    steps:
+      - name: 'Update floating tag'
+        uses: 'actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea' # ratchet:actions/github-script@v7
+        env:
+          RELEASE_VERSION: 'v${{ needs.create-release.outputs.version }}'
+          REPO: '${{ github.repository }}'
+        with:
+          github-token: '${{ secrets.ACTIONS_BOT_TOKEN }}'
+          script: |-
+            const tag = process.env.RELEASE_VERSION;
+            const major = tag.split(".")[0];
+            const githubActionsRef = `${process.env.REPO}@${major}`
+
+            // Try to update the ref first. If that fails, it probably does not
+            // exist yet, and we should create it.
+            try {
+              await github.rest.git.updateRef({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                ref: "tags/" + major,
+                sha: context.sha,
+                force: true,
+              });
+              core.info(`Updated ${githubActionsRef} to ${context.sha} (${tag})`);
+            } catch (err) {
+              core.warning(`Failed to create tag ${major}: ${err}`);
+
+              await github.rest.git.createRef({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                ref: "refs/tags/" + major,
+                sha: context.sha,
+              });
+              core.info(`Created ${githubActionsRef} at ${context.sha} (${tag})`);
+            }
+
   cleanup-failed-release:
     if: |-
       ${{ always() && needs.create-release.outputs.created == 'true' && contains(fromJSON('["failure", "cancelled", "skipped"]'), needs.publish-release.result) }}