docs: Update README.md

Close #15

README.md

@@ -1,6 +1,6 @@
 # docker-coq-github-action-demo
 
-[![Docker CI](https://github.com/erikmd/docker-coq-github-action-demo/workflows/Docker%20CI/badge.svg?branch=master)](https://github.com/erikmd/docker-coq-github-action-demo/actions?query=workflow:"Docker%20CI")
+[![Docker CI](https://github.com/erikmd/docker-coq-github-action-demo/actions/workflows/build-coq-demo.yml/badge.svg?branch=master)](https://github.com/erikmd/docker-coq-github-action-demo/actions/workflows/build-coq-demo.yml)
 
 Demo of:
 
@@ -13,9 +13,15 @@ Demo of:
 Note: you can add a badge in your `README.md`, like that of this demo:
 
 ```
-[![Docker CI](https://github.com/$USER/$REPO/workflows/Docker%20CI/badge.svg?branch=master)](https://github.com/$USER/$REPO/actions?query=workflow:"Docker%20CI")
+[![Docker CI](https://github.com/$USER/$REPO/actions/workflows/build.yml/badge.svg?branch=master)](https://github.com/$USER/$REPO/actions/workflows/build.yml)
 ```
 
-after replacing `$USER/$REPO` to use your project namespace; note also
-that "Docker CI" is the workflow name, defined at the beginning of
-[this file](./.github/workflows/build-coq-demo.yml).
+after replacing `$USER/$REPO` to use your project namespace and `build.yml`
+with your workflow YAML file name.
+
+**Important:** this demo repository is not actively maintained, it especially
+serves now as a coq project example for
+[docker-coq-action's CI](https://github.com/coq-community/docker-coq-action/actions/workflows/coq-demo.yml), so as a coq or ocaml user, you may
+be interested to use
+[coq-community's CI templates](https://github.com/coq-community/templates#readme) instead,
+which also rely on **docker-coq-action**.