Tweak github action used to detect changed paths on push/pull request

Author: maxstack

.github/workflows/main.yml

@@ -84,8 +84,7 @@ jobs:
             stackhpc:
               - '**'
               - '!dev/**'
-              - '!docs/**'
-              - '!README.md'
+              - '!**.md'
               - '!.gitignore'
               - '!.github/workflows/'