restrict doc publication to branch main

Author: Fabien Coelho

.github/workflows/docs.yml

@@ -1,6 +1,8 @@
 name: FlaskTest documentation publication on GitHub
 
-on: push
+on:
+  push:
+    branches: [ "main" ]
 
 jobs:
   build:

docs/versions.md

@@ -8,6 +8,7 @@ please report any [issues](https://github.com/zx80/flask-tester/issues).
 ## TODO
 
 Check whether data and json should be exclusive.
+Publish documentation only when pushing on branch `main`.
 
 ## ? on ?