Improve GitHub Actions (#97)

* Delete hassfest.yaml

* Update and rename ci.yaml to tox.yaml

* Create combined.yaml

* Update hacs.json

* Update README.md

* Update combined.yaml

* Remove unused import

* Restored wrongly deleted line in cover.py

* Update config_flow.py

* Update __init__.py

Co-authored-by: Pierre Ståhl <pierre.staahl@gmail.com>
Co-authored-by: rospogrigio <49229287+rospogrigio@users.noreply.github.com>

.github/workflows/combined.yaml

@@ -0,0 +1,26 @@
+name: "Validation And Formatting"
+on:
+  push:
+  pull_request:
+  schedule:
+    - cron: '0 0 * * *'
+jobs:
+  ci:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        name: Download repo
+        with:
+          fetch-depth: 0
+      - uses: actions/setup-python@v2
+        name: Setup Python
+      - uses: actions/cache@v2
+        name: Cache
+        with:
+          path: |
+            ~/.cache/pip
+          key: custom-component-ci
+      - uses: KTibow/ha-blueprint@stable
+        name: CI
+        with:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}