[releases] Don't create github releases for cloud RCs (#1313)

Summary: There was a slight bug that slipped through which meant GitHub
releases were only being created for cloud RCs instead of only for full
releases.

Type of change: /kind cleanup

Test Plan: N/A

Signed-off-by: James Bartlett <jamesbartlett@pixielabs.ai>

Author: JamesMBartlett

.github/workflows/cloud_release.yaml

@@ -50,7 +50,7 @@ jobs:
         name: cloud-artifacts
         path: artifacts/
   create-github-release:
-    if: ${{ contains(github.event.ref, '-') }}
+    if: ${{ !contains(github.event.ref, '-') }}
     name: Create Release on Github
     runs-on: ubuntu-latest
     needs: build-release