Update build.yml

Split up build tasks in workflow

Author: Htbaa

.github/workflows/build.yml

@@ -21,10 +21,10 @@ jobs:
           cache: 'npm'
       - name: Install Node.js dependencies
         run: npm install
-      - name: Build Javascript & CSS
+      - name: Build Javascript
         env:
           # Fix for ERR_OSSL_EVP_UNSUPPORTED error caused by Webpack
           NODE_OPTIONS: --openssl-legacy-provider
-        run: |
-          npm run css-dev
-          npm run webpack-dev
+        run: npm run webpack-dev
+      - name: Build CSS
+        run: npm run css-dev