add gulp action for building devicon.min.css

.github/workflows/build_icons.yml

@@ -14,14 +14,15 @@ jobs:
       - uses: actions/checkout@v2
         with:
           ref: ${{ github.head_ref }}
-      - name: Set up Python 3.8
+      - name: Setup Python v3.8
         uses: actions/setup-python@v2
         with: 
           python-version: 3.8
-      - name: Install dependencies
+      - name: Install dependencies (python, pip, npm)
         run: |
           python -m pip install --upgrade pip
           pip install -r ./.github/scripts/requirements.txt
+          npm install
       - name: Run icomoon_upload.py
         run: >
           python ./.github/scripts/icomoon_upload.py 
@@ -32,6 +33,9 @@ jobs:
         with:
           name: geckodriver-log
           path: ./geckodriver.log
+      - name: Running gulp default task for building devicon.min.css
+        run: |
+          gulp default
       - name: Commit changes
         uses: stefanzweifel/git-auto-commit-action@v4
         with: