Prevent file loss/exceptions when renaming

[spdjudd]

Fixes issue #277

Change Summary

1. Do nothing if renaming a file to have the same path as it currently has - previously the file was unlinked then an exception raised when trying to copy
2. Raise an explicit exception when attempting to rename a directory - the implementation only supports rename/replace of files, which raises an exception from within _move_file() if passed a directory

Tests

I've added test conditions where it seemed appropriate within the existing test methods to exercise these changes - happy to move to separate test methods if preferred?

[pjbull]

Does pathlib error if you call replace on a directory? I assume not. If not, can we add an issue to track implementing replace for directories?

[spdjudd]

Sure - I just checked and pathlib replace and rename both work for directories - I'll go ahead and add the issue

[spdjudd]

Actually I just checked and I think this is already logged as issue #64

[pjbull]

Thanks @spdjudd. If all the tests except the live server ones pass, I'll move these over to a local fork to make sure everything works there and then merge. Would you mind filing the issue I mentioned above?

[codecov-commenter]

Codecov Report

Merging #278 (5ca7b71) into master (b7f6010) will decrease coverage by 0.3%.
The diff coverage is 100.0%.

Additional details and impacted files

@@           Coverage Diff            @@
##           master    #278     +/-   ##
========================================
- Coverage    94.8%   94.4%   -0.4%     
========================================
  Files          20      20             
  Lines        1314    1318      +4     
========================================
- Hits         1246    1245      -1     
- Misses         68      73      +5     

Impacted Files	Coverage Δ
cloudpathlib/cloudpath.py	93.6% <100.0%> (+<0.1%)	⬆️
cloudpathlib/s3/s3client.py	92.9% <0.0%> (-2.7%)	⬇️
cloudpathlib/gs/gsclient.py	92.8% <0.0%> (-1.8%)	⬇️