Fix diff in wiki notifications (use full clone)

The checkout action fetches one single commit, so attempts to find previous states of a page result in error. Adding fetch-depth:0 to the configuration fetches all commits and makes finding the previous commit that changed a page possible in the github action.

.github/workflows/wiki-monitor.yml

@@ -12,6 +12,7 @@ jobs:
         with:
           repository: ${{ github.repository }}.wiki
           path: wiki
+          fetch-depth: 0
 
       - name: Generate wiki change message
         run: |
@@ -58,3 +59,4 @@ jobs:
 
 
 
+