another try at wrangler stuff

.github/workflows/build.yml

@@ -62,6 +62,8 @@ jobs:
               with:
                   node-version: '14'
 
+            - run: npm i -g @cloudflare/wrangler
+
             - name: Get yarn cache directory path
               id: yarn-cache-dir-path
               run: echo "::set-output name=dir::$(yarn cache dir)"
@@ -76,7 +78,10 @@ jobs:
 
             - run: yarn install --frozen-lockfile
 
-            - run: yarn wrangler build
+            - run: |
+                  wrangler init
+                  echo 'webpack_config = "src/backend-worker/webpack.config.js"' | tee -a wrangler.toml
+                  wrangler build
 
             - name: Set up Cloud SDK
               uses: google-github-actions/setup-gcloud@master