Upload hidden files for staging during release (#749)

Motivation:

Due a change in the upload action of github we now need to explicit
enable the uplaod of hidden files (dot-files). Not doing this breaks our
staging workflow which depends on some of these files.

See actions/upload-artifact#602

Modifications:

Explicit set include-hidden-files: true

Result:

Staging works again

.github/workflows/ci-release.yml

@@ -152,6 +152,7 @@ jobs:
           name: ${{ matrix.setup }}-local-staging
           path: ~/local-staging
           if-no-files-found: error
+          include-hidden-files: true
 
       - name: Rollback release on failure
         working-directory: ./prepare-release-workspace/