[ci] make badges clickeable

Author: vvolkl

README.md

@@ -1,5 +1,5 @@
 # GitHub Action: cvmfs-contrib/github-action-cvmfs
-[![ubuntu](https://github.com/cvmfs-contrib/github-action-   cvmfs/workflows/ubuntu/badge.svg)](https://github.com/cvmfs-contrib/github-action-cvmfs/actions?query=workflow%3Aubuntu) [![macOS](https://github.com/cvmfs-contrib/github-action-   cvmfs/workflows/macOS/badge.svg)](https://github.com/cvmfs-contrib/github-action-cvmfs/actions?query=workflow%3AmacOS)
+[![ubuntu](https://github.com/cvmfs-contrib/github-action- cvmfs/workflows/ubuntu/badge.svg)](https://github.com/cvmfs-contrib/github-action-cvmfs/actions?query=workflow%3Aubuntu) [![macOS](https://github.com/cvmfs-contrib/github-action-cvmfs/workflows/macOS/badge.svg)](https://github.com/cvmfs-contrib/github-action-cvmfs/actions?query=workflow%3AmacOS)
 
 
 This GitHub Action sets up CernVM-FS for use in GitHub Workflows.