Let dependabot decide of the python version

.drone.yml

@@ -4,7 +4,7 @@ type: docker
 
 steps:
   - name: flake8
-    image: python
+    image: python:slim
     commands:
       - pip install flake8
       - flake8 pynyaata --ignore=E501

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:slim
+FROM python:3.9.1-slim
 
 COPY pynyaata /app/pynyaata
 COPY requirements.txt *.py /app/