Change to python 3.9 (#118)

* Bump dockerfile to python 3.9

* More python 3.9 only

.github/workflows/pytest.yaml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.7", "3.8", "3.9"]
+        python-version: ["3.9"]
 
     steps:
       - uses: actions/checkout@v3

Dockerfile

@@ -1,5 +1,5 @@
 # inspired by https://medium.com/@harpalsahota/dockerizing-python-poetry-applications-1aa3acb76287
-FROM python:3.7
+FROM python:3.9
 
 RUN mkdir /app /data
 WORKDIR /app

README.md

@@ -20,7 +20,7 @@ Docker image is created automatically and available at dockerhub: [maxwinterstei
 
 ### Native
 
-- Create some virtualenv (or what you personally prefer) with at least python 3.7
+- Create some virtualenv (or what you personally prefer) with at least python 3.9
 - Install requirements `pip install -r requirements.txt`
 - Install TooGoodToGoo Home Assistant Mqtt Bridge `pip install .`