hardcode hugo version until "withdeploy" works

   Will need actions-hugo to support `withdeploy: true` from
   peaceiris/actions-hugo#659 and then this can be changed
   back to 'latest'.

.github/workflows/deploy.yaml

@@ -16,8 +16,9 @@ jobs:
     - name: Install Hugo
       uses: peaceiris/actions-hugo@v3
       with:
-        hugo-version: latest
+        hugo-version: '0.136.0'
         extended: true
+        withdeploy: true
     - name: Cache
       uses: actions/cache@v2
       with: