Add session passing to functions

[samdixon]

• Adds ability to pass session variable to get_password, set_password, and delete_password functions. Default = None.
• Adds tests for new functionality with 100% coverage.
  • Double check these tests for validity. I don't have much exp writing tests.
• Minor version bump from 0.2.1 to 0.2.2

[codecov[bot]]

Codecov Report

Merging #4 into master will not change coverage. The diff coverage is 100%.

@@          Coverage Diff          @@
##           master     #4   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           1      1           
  Lines         155    158    +3     
  Branches       18     21    +3     
=====================================
+ Hits          155    158    +3

Impacted Files	Coverage Δ
bitwarden_keyring/__init__.py	100% <100%> (ø)	:arrow_up:

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