Update to new upstream version

Some refactoring had to be done due to changes in the upstream layout - there's now a 3-level nested set of directories, so simple iteration doesn't work anymore.

There are also missing dependencies reported on opencensus and opentelemetry:

I: dh_python3 pydist:228: Cannot find package that provides opentelemetry_api. Please add package that provides it to Build-Depends or add "opentelemetry_api python3-opentelemetry-api" line to debian/py3dist-overrides or add proper dependency to Depends by hand and ignore this info.
I: dh_python3 pydist:228: Cannot find package that provides opencensus_ext_azure. Please add package that provides it to Build-Depends or add "opencensus_ext_azure python3-opencensus-ext-azure" line to debian/py3dist-overrides or add proper dependency to Depends by hand and ignore this info.
I: dh_python3 pydist:228: Cannot find package that provides opencensus_ext_threading. Please add package that provides it to Build-Depends or add "opencensus_ext_threading python3-opencensus-ext-threading" line to debian/py3dist-overrides or add proper dependency to Depends by hand and ignore this info.
I: dh_python3 pydist:228: Cannot find package that provides opencensus. Please add package that provides it to Build-Depends or add "opencensus python3-opencensus" line to debian/py3dist-overrides or add proper dependency to Depends by hand and ignore this info.

They seem to be both optional, so I filter those modules out.