Chore: Update Python and req versions

Dockerfile

-FROM python:3.8-slim
+FROM python:3.9-slim
 
 LABEL maintainer="David Trattnig <david.trattnig@subsquare.at>"
 

requirements.txt

 requests==2.24.0
-connexion >= 2.7.0
-connexion[swagger-ui] >= 2.7.0
-python_dateutil == 2.6.0
-typing == 3.5.2.2
-setuptools >= 21.0.0
+connexion>=2.8.0
+connexion[swagger-ui]>=2.8.0
+python_dateutil==2.6.0
+typing==3.5.2.2
+setuptools>=21.0.0
 gunicorn==20.0.4
 sqlalchemy==1.3.17
 Flask_SQLAlchemy==2.4.3
 flask-marshmallow==0.13.0
 marshmallow-sqlalchemy==0.23.1
 wheel==0.37.0
-swagger-ui-bundle >= 0.0.2
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+swagger-ui-bundle>=0.0.2
+click>=8.0.0
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