Fix markdown links job (#255)

Author: andyblundell

.github/workflows/action.yml

@@ -7,6 +7,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@master
-    - uses: gaurav-nelson/github-action-markdown-link-check@v1.0.13
+    - uses: gaurav-nelson/github-action-markdown-link-check@1.0.13
       with:
         use-quiet-mode: 'yes'