extra action for PR

Author: lukruh

.github/workflows/link-checker-pr.yml

@@ -1,9 +1,8 @@
-name: Check Links
+name: Check Links in PRs
 
 on:
-  push:
-    branches:
-      - link_checker  # TODO: change to main to after testing
+  pull_request:
+    paths: ['**.md']
   workflow_dispatch:
 
 jobs:
@@ -16,14 +15,11 @@ jobs:
         id: lychee
         uses: lycheeverse/lychee-action@v2
         with:
-          fail: false
-          # args to check source files without building
-          # './**/*.md' './**/*.html' './**/*.rst'
-          args: >
-            ./_site/**/*.html
-            --max-concurrency 1 --no-progress 
-            --accept '100..=103,200..=399, 429'
-            --exclude https://doi.org/
+          fail: true
+          args: |
+            './**/*.md'
+            --max-concurrency 1
+            --no-progress 
         env:
           # avoid 429 errors (too many requests) on github.com api requests
           GITHUB_TOKEN: ${{secrets.TOKEN_GITHUB}}