Merge master into 0.2 branch

I agreed with @mark that I shoud tag current HEAD with a new tag (0.2.9) which we can use for openappstacks 0.6.0 release (https://open.greenhost.net/openappstack/openappstack/-/issues/837). This MR merges current master head into the 0.2 branch.

test/integration_tests/Dockerfile

@@ -9,6 +9,7 @@ RUN apk --no-cache add \
     python3-dev \
     libc-dev \
     openssl-dev \
+    bash \
     gcc
 
 RUN pip3 install --no-cache-dir -r requirements.txt