Skip upload jobs if release is an RC by checking the ref for a rc suffix

This makes sure we don't upload RCs as trunk or tag even if the deployer accidentally unchecks the "Set as prerelease" flag.

.github/workflows/upload-release-to-plugin-repo.yml

@@ -8,6 +8,13 @@ jobs:
     compute-should-update-trunk:
         name: Decide if trunk or tag
         runs-on: ubuntu-latest
+        # Skip this job if the release is a release candidate. This will in turn skip
+        # the upload jobs, which are only relevant for non-RC releases.
+        # We first check if the release is a prerelease, and then if the ref contains
+        # the string "rc". The latter is fallback in case the deployer accidentally
+        # unchecks the "This is a pre-release" checkbox in the release UI.
+        if: |
+            !github.event.release.prerelease || !contains(github.ref, 'rc')
         outputs:
             should_update_trunk: ${{ steps.compute_should_update_trunk.outputs.should_update_trunk }}
 
@@ -156,8 +163,7 @@ jobs:
         environment: wp.org plugin
         needs: [compute-should-update-trunk, update-changelog]
         if: |
-            needs.compute-should-update-trunk.outputs.should_update_trunk == 'true' &&
-            !github.event.release.prerelease && github.event.release.assets[0]
+            needs.compute-should-update-trunk.outputs.should_update_trunk == 'true' && github.event.release.assets[0]
         env:
             PLUGIN_REPO_URL: 'http://caffeine.ngrok.io/svn/gutenberg'
             STABLE_VERSION_REGEX: '[0-9]\+\.[0-9]\+\.[0-9]\+\s*'
@@ -220,8 +226,7 @@ jobs:
         environment: wp.org plugin
         needs: [compute-should-update-trunk, update-changelog]
         if: |
-            needs.compute-should-update-trunk.outputs.should_update_trunk == 'false' &&
-            !github.event.release.prerelease && github.event.release.assets[0]
+            needs.compute-should-update-trunk.outputs.should_update_trunk == 'false' && github.event.release.assets[0]
         env:
             PLUGIN_REPO_URL: 'http://caffeine.ngrok.io/svn/gutenberg'
             STABLE_VERSION_REGEX: '[0-9]\+\.[0-9]\+\.[0-9]\+\s*'