Fix Markdown Anchor Link Check (#722)

**Why?**

With the release of MegaLinter v7.11.0, the markdown-link-check dependency was
upgraded to v3.12.1. This, however, fails checks where anchor links are used.

**What?**

Fixed the MegaLinter workflow to v7.10.0 for now.
We can revert this change/loosen the requirement to v7 when the issue is
resolved later on.

.github/workflows/mega-linter.yml

@@ -27,7 +27,11 @@ jobs:
 
       - name: MegaLinter
         id: ml
-        uses: oxsecurity/megalinter@v7
+        # MegaLinter v7.11 upgrades Markdown-Link-Check to v3.12.1
+        # This version broke anchor link checks according to:
+        # https://github.com/tcort/markdown-link-check/issues/304
+        # Setting the version to v7.10.0 for now:
+        uses: oxsecurity/megalinter@v7.10.0
         env:
           # All available variables are described in documentation
           # https://megalinter.io/configuration/