Fix nested remove for azure and gcs

[pjbull]

Closes #184

Problem is that _list_dir implementations return both directories and files, but our _remove function for both of these clients assumes only files.

Added regression test which fails on Azure + GCS without this fixes, but passes with the fix.

Updated history and version to cut new release with this fix

[github-actions]

🚀 Deployed on https://deploy-preview-185--gallant-agnesi-5f7bb3.netlify.app

[codecov]

Codecov Report

Merging #185 (ba45cfb) into master (3901746) will not change coverage.
The diff coverage is 100.0%.

@@          Coverage Diff           @@
##           master    #185   +/-   ##
======================================
  Coverage    94.1%   94.1%           
======================================
  Files          21      21           
  Lines        1189    1189           
======================================
  Hits         1120    1120           
  Misses         69      69           

Impacted Files	Coverage Δ
cloudpathlib/azure/azblobclient.py	94.6% <100.0%> (ø)
cloudpathlib/gs/gsclient.py	94.0% <100.0%> (ø)

[pjbull]

@jayqi Going to merge this since I think this is low-risk and well-tested so that we can cut a release to fix #184.

Happy to address any code review comments in separate PR.

[jayqi]

Looks okay. The main thing that stands out to me is that this may have a performance impact from additional network calls.