Use new context invocation class to cache environment variables.

[peterallenwebb]

resolves #

Problem

Solution

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX
• This PR includes type annotations for new and modified functions

[github-actions]

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[MichelleArk]

Changes look good overall. I guess we'll need to release on dbt-common first with the corresponding changes in dbt-labs/dbt-common#52 to see CI passing

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (1a5d692) 88.04% compared to head (3e8820c) 87.96%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
core/dbt/logger.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9489      +/-   ##
==========================================
- Coverage   88.04%   87.96%   -0.08%     
==========================================
  Files         167      167              
  Lines       22126    22171      +45     
==========================================
+ Hits        19480    19503      +23     
- Misses       2646     2668      +22     

Flag	Coverage Δ
integration	85.42% <88.37%> (-0.17%)	⬇️
unit	62.36% <74.41%> (+<0.01%)	⬆️

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[MichelleArk]

nit: is ci the InvocationContext? If so, we can name it ic and type annotate for clarity

[peterallenwebb]

oops, yes