Caching docker image.

.github/workflows/mkdocs.yml

@@ -12,6 +12,10 @@ jobs:
       - name: Checkout main
         uses: actions/checkout@v1
 
+      - uses: satackey/action-docker-layer-caching@v0.0.11
+        # Ignore the failure of a step and avoid terminating the job.
+        continue-on-error: true
+
       - name: Deploy docs
         uses: nicolasnoble/mkdocs-deploy-gh-pages@master
         # Or use mhausenblas/mkdocs-deploy-gh-pages@nomaterial to build without the mkdocs-material theme