Create check_links.yml

Author: ahpaleus

.github/workflows/check_links.yml

@@ -0,0 +1,21 @@
+name: Check Markdown links
+
+on: 
+  push:
+    branches:
+      - master
+    paths:
+      - '**.md'
+    pull_request:
+      paths:
+        - '**.md'
+
+jobs:
+  markdown-link-check:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@master
+    - uses: gaurav-nelson/github-action-markdown-link-check@v1
+      with:
+        use-quiet-mode: 'yes'
+        use-verbose-mode: 'yes'