Install wheel before building mmseg (open-mmlab#14)

Author: hellock

.github/workflows/deploy.yml

@@ -13,7 +13,9 @@ jobs:
         with:
           python-version: 3.7
       - name: Build MMSegmentation
-        run: python setup.py sdist bdist_wheel
+        run: |
+          pip install wheel
+          python setup.py sdist bdist_wheel
       - name: Publish distribution to PyPI
         run: |
           pip install twine