ci: Update cache key for .ghcup directory

Author: develop7

.github/actions/build-generator/action.yaml

@@ -12,7 +12,7 @@ runs:
       uses: actions/cache@v4.3.0
       with:
         path: ~/.ghcup
-        key: ${{ runner.os }}-stack-${{ hashFiles('generator/stack.yaml.lock') }}
+        key: ${{ runner.os }}-ghcup
     - name: Cache .stack directory
       uses: actions/cache@v4.3.0
       with: