Add support for HelmRelease that depends on the local GitRepository

[allenporter]

Allow optimistically building GitRepository assuming they point at the local repo.

Issue #616

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 97.67442% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 93.54%. Comparing base (6b247c9) to head (e74892c).
Report is 1 commits behind head on main.

Files	Patch %	Lines
flux_local/helm.py	88.88%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #638   +/-   ##
=======================================
  Coverage   93.54%   93.54%           
=======================================
  Files          20       20           
  Lines        2106     2122   +16     
=======================================
+ Hits         1970     1985   +15     
- Misses        136      137    +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.