Problem: jobs in system debian fail

Solution: install debian package python3-setuptools, -wheel and -coverage.

.circleci/config.yml

@@ -72,7 +72,7 @@ workflows:
       - test:
           matrix:
             parameters:
-              python-version: ["3.8"]
+              python-version: ["3.9"]
               build-type: ["debian_sys_container"]
   tests-ubuntu-machines:
     jobs:

.github/workflows/Dockerfile-debian-system

 FROM debian:stable-slim as debian-python
 RUN apt-get update
-RUN apt-get install -y gcc python3-dev python3-certifi
+RUN apt-get install -y gcc python3-dev python3-certifi python3-setuptools python3-coverage python3-wheel
 RUN useradd -ms /bin/bash buildout
 USER buildout
 RUN mkdir /home/buildout/sandbox

.github/workflows/debian-sys.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.8]
+        python-version: [3.9]
 
     steps:
     - uses: actions/checkout@v2