Merge pull request #3521 from dapr/greenie-msft-patch-9

Update link_validation.yaml to temporarily fix docs link validation error

.github/workflows/link_validation.yaml

@@ -34,6 +34,8 @@ jobs:
         run: |
           python3 -m pip install --upgrade pip
           pip3 install setuptools wheel twine tox mechanical-markdown
+          pip3 uninstall -y mistune
+          pip3 install mistune~=2.0.5 --no-cache-dir
       - name: Check Markdown Files
         run: |
           for name in `find . -name "*.md"`; do echo -e "------\n$name" ; mm.py -l $name || exit 1 ;done