Set required labels on the automatic pack version update PRs

When a new Pack CLI version is released, automation opens PRs like:
#227

Currently the human reviewer has to remember to set the semver
and type labels on that PR in order for the status checks to pass.

Now, the automation will set these itself on the PR.

.github/workflows/update-pack-version.yml

@@ -30,6 +30,9 @@ jobs:
             
             Release notes:
             https://github.com/buildpacks/pack/releases/tag/v${{ steps.version.outputs.new_version }}
+          labels: |
+            semver:patch
+            type:dependency-upgrade
           branch: update-version
           base: main
           signoff: true