Add cli upgrade/management support

[calebcartwright]

Changes

• [X] Enhance the git hook scripts to check the version of the cli, and upgrade if the cli version is older than the minimum required version
• [X] Split some of the supporting functions for the git hooks into separate files
• [X] Add test scaffolding for hook script files
• [X] Add unit tests for the hook script functions
• [x] Add PR job for hook script validation (runs shellcheck and unit tests)

Related Issues

• Closes #46
• Closes #54
• Closes #56

[codecov[bot]]

Codecov Report

Merging #55 into master will not change coverage. The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #55   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           3      4    +1     
  Lines         141    169   +28     
=====================================
+ Hits          141    169   +28

Impacted Files	Coverage Δ
src/hooks.rs	100% <100%> (ø)
src/git.rs	100% <100%> (ø)	:arrow_up:
src/rusty_hook.rs	100% <100%> (ø)	:arrow_up:

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