Add permissions to Github workflows to bump version

On personal repos, Github workflows have write permission by default. However, on team account repos, Github workflows do not have write permission. Therefore, this commit grant permission to the workflow.

See details of Github workflow permissions https://docs.github.com/en/actions/using-jobs/assigning-permissions-to-jobs

.github/workflows/bump_version.yml

@@ -16,6 +16,9 @@ on:
 
 jobs:
   create-pull-requests:
+    permissions:
+      contents: write
+      pull-requests: write
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2