Fix github release trigger

The `git.ref` variable includes the `refs/tags/` prefix [0].

[0]: https://docs.github.com/en/actions/reference/context-and-expression-syntax-for-github-actions#github-context

Change-Id: I2880c7cc1463e52cc8ca6605db80b2a46cb5a449

.github/workflows/release.yaml

@@ -89,7 +89,7 @@ jobs:
 
   release-github:
     # Only create github releases for airshipctl (unprefixed semver tag), not krm functions.
-    if: ${{ startsWith(github.ref, 'v') }}
+    if: ${{ startsWith(github.ref, 'refs/tags/v') }}
     runs-on: ubuntu-latest
     steps:
       - name: Checkout