Release 2022.6.0

[consideRatio]

I'd like to cut a release to help fix a bug in dask-gateway client that otherwise forces a workaround of not using a modern version of distributed.

Todo

• Resolve Fix compatibility with distributed >= 2022.5.1 and traitlets >= 5.2.0, and raise the lower bound of required versions #573
• Resolve Provide frozen requirements.txt files for images, and automation to update them #575
• Create changelog according to RELEASE.md documentation
• Cut a release according to RELEASE.md documentation

[consideRatio]

2022.6.0 was released, but I was frustrated about a mistake I realized I made. I constrainted dask-gateway the client to not use distributed 2022.5.1 and 2022.5.2 while in the same PR I made dask-gateway the client compatible with those version, making the constraint not needed.

While verifying that we did now have support for distributed==2022.5.1 and 2022.5.2, I also concluded that the lower bound were still too optimistic, and we in practice require distributed>=2022.4.0. So, in #580 that was resolved, and I'll go for a 2022.6.1 release.

[consideRatio]

2022.6.0 and 2022.6.1 has been released to PyPI. A release to conda forge remains to be made in https://github.com/conda-forge/dask-gateway-feedstock/pulls though - a PR should be opened in time there.