ci(release-please): fix workflow permissions (#382)

Follows #352

Signed-off-by: Marco Nenciarini <[email protected]>

Author: mnencia

.github/workflows/release-please.yml

@@ -13,6 +13,7 @@ jobs:
     permissions:
       contents: write
       pull-requests: write
+      packages: write
     steps:
       # TODO: googleapis/release-please-action cannot sign commits yet.
       #   We'll use the cli until there's a fix for