Misc Python update / signal / child-workflow features #821

Job	Run time
build-dotnet (ubuntu-latest)	28s
build-go (ubuntu-latest)	30s
build-java (ubuntu-latest)	1m 9s
build-python (ubuntu-latest)	24s
build-ts (ubuntu-latest)	21s
feature-tests-dotnet / test	50s
feature-tests-java / test	2m 49s
feature-tests-go / test	2m 5s
feature-tests-ts / test	1m 58s
feature-tests-python / test	1m 22s
build-docker-images / build-dotnet-docker-images / Build cs docker image	1m 41s
build-docker-images / build-go-docker-images / Build go docker image	2m 42s
build-docker-images / build-java-docker-images / Build java docker image	3m 24s
build-docker-images / build-python-docker-images / Build py docker image	2m 34s
build-docker-images / build-ts-docker-images / Build ts docker image	2m 59s
	25m 16s

Provide feedback