Fix link checker: stop forcing checkout of gh-pages (use current commit/branch)

Author: arnavk23

.github/workflows/LinkChecker.yml

@@ -13,8 +13,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-        with:
-          ref: 'gh-pages'
 
       - name: Link Checker
         uses: lycheeverse/[email protected]