ci: fix docker yaml file

Author: f-necas

.github/workflows/docker.yml

@@ -11,6 +11,10 @@ on:
 
 jobs:
   build:
+    if: "!startsWith(github.event.head_commit.message, '[skip ci] ')"
+    runs-on: ubuntu-latest
+    timeout-minutes: 40
+    steps:
     - name: Getting image tag
       if: github.repository == 'georchestra/geonetwork' && github.actor != 'dependabot[bot]'
       id: version