Prevent "alpine:edge" from failling the workflow

Alpine is releases a new version once a year. Therefore our workflow
runs don't need to be marked as failed when run on alpine:edge

Author: tobiasge

.github/workflows/push.yml

@@ -10,6 +10,7 @@ on:
 
 jobs:
   build:
+    continue-on-error: ${{ matrix.docker_from == 'alpine:edge' }}
     strategy:
       matrix:
         build_cmd: