Remove check link diff for now

Error:

fatal: ambiguous argument 'origin/master': unknown revision or path not
in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'

After migration to github page actions we can review it

.github/workflows/pull-requests.yml

@@ -1,4 +1,4 @@
-name: Checking Pull Requests
+name: Checking Pull Request
 
 on: pull_request
 
@@ -19,6 +19,3 @@ jobs:
 
     - name: Run tests
       run: npm test
-
-    - name: Check links
-      run: npm run check-link-diff