Support for specifying error types with retry

[barshaul]

Pull Request check-list

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Description of change

The current client implementation supports only retry on TimeoutError.
Added support for passing specific error types to use with the retry mechanism.
The 'retry_on_timeout' argument has not changed for backward compatibility.
Closes #1764

[codecov-commenter]

Codecov Report

Merging #1817 (15d0ada) into master (18c6809) will decrease coverage by 0.33%.
The diff coverage is 97.87%.

@@            Coverage Diff             @@
##           master    #1817      +/-   ##
==========================================
- Coverage   94.29%   93.96%   -0.34%     
==========================================
  Files          75       75              
  Lines       15783    15328     -455     
==========================================
- Hits        14883    14403     -480     
- Misses        900      925      +25     

Impacted Files	Coverage Δ
redis/client.py	89.75% <75.00%> (-0.22%)	⬇️
redis/cluster.py	90.22% <85.71%> (-0.08%)	⬇️
redis/connection.py	88.78% <100.00%> (+0.08%)	⬆️
redis/retry.py	95.65% <100.00%> (-4.35%)	⬇️
tests/test_retry.py	100.00% <100.00%> (ø)
tests/test_ssl.py	85.71% <0.00%> (-5.96%)	⬇️
redis/__init__.py	85.71% <0.00%> (-4.77%)	⬇️
tests/test_graph_utils/test_edge.py	93.93% <0.00%> (-3.36%)	⬇️
tests/test_graph.py	87.39% <0.00%> (-2.53%)	⬇️
... and 36 more

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[chayim]

Looks good overall. Given the new retry_on_error having a list value, I really think it's default should be at least, an empty list (see inline).