Update ghpages GitHub actions workflow

Author: JKRhb

.github/workflows/ghpages.yml

@@ -30,7 +30,7 @@ jobs:
         date -u "+::set-output name=date::%FT%T"
 
     - name: "Cache References"
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: |
           ${{ steps.cache-setup.outputs.path }}
@@ -53,7 +53,7 @@ jobs:
         token: ${{ github.token }}
 
     - name: "Archive Built Drafts"
-      uses: actions/upload-artifact@v2
+      uses: actions/upload-artifact@v4
       with:
         path: |
           draft-*.html