Validate links in changed markdown files

New workflow gets the list of markdown files modified
and runs `mlc` Markup Line Checker tool on those file.

Signed-off-by: Sudan Landge <[email protected]>

.github/workflows/markdown_link_checker.yml

@@ -0,0 +1,28 @@
+name: Check links in markdown documentation
+
+on: pull_request
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: "Checkout repository"
+        uses: actions/checkout@v3
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+
+      - name: "Validate links in updated markdown files"
+        run: |
+          git fetch origin
+          changedFiles=$(git diff origin/$GITHUB_BASE_REF.. --name-only)
+          mlc_installed=0
+          for file in $changedFiles; do
+            if [[ ".md" == ".${file##*.}" ]]; then
+              if [[ $mlc_installed == 0 ]]; then
+                cargo install mlc
+                mlc_installed=1
+              fi
+              echo ${file};
+              mlc $file
+            fi
+          done