Update HACS validation to use main instead of master.

.github/workflows/hacs-validate.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
       - uses: 'actions/checkout@v2'
       - name: HACS validation
-        uses: 'hacs/integration/action@master'
+        uses: 'hacs/integration/action@main'
         with:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           CATEGORY: 'integration'