add google cloud build envs

[dfrankland]

Took some diffing to figure this one out
https://docs.cloud.google.com/build/docs/configuring-builds/substitute-variable-values

Also, these are not automatically provided. We'll have to guide users to passing the necessary env vars 😬

Google Cloud Build setup is very involved, so I haven't attempted at setting this up myself.

[trunk-io]

😎 Merged directly without going through the merge queue, as the queue was empty and the PR was up to date with the target branch - details.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 91.30435% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.67%. Comparing base (55a2cf8) to head (1d1d689).

Files with missing lines	Patch %	Lines
context/src/env/parser.rs	91.30%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1031      +/-   ##
==========================================
+ Coverage   81.39%   81.67%   +0.27%     
==========================================
  Files          69       69              
  Lines       14547    14566      +19     
==========================================
+ Hits        11841    11897      +56     
+ Misses       2706     2669      -37     

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[trunk-staging-io]

     

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[dfrankland]

Because either Jekins or Google Cloud Build may provide BUILD_ID we need to prioritize Google Cloud Build if we detect it

[max-trunk]

IIUC the CIPlatform will only be anything other than Unknown if the current env var we're interrogating / trying to prioritize off of is a ci_platform_env_key (based on the CIPlatform::from() here) - which only Jenkins's ci_platform_env_key is BUILD_ID. So perhaps this isn't explicitly needed? Or I'm misinterpreting

[dfrankland]

The problem is that we don't guarantee the order of env vars we receive. So we could get BUILD_ID before TRIGGER_NAME. If we get both, then we need to decide which one to use: in the case of Jenkins and Google Cloud Build, Google Cloud Build can have BUILD_ID, but Jenkins will not have TRIGGER_NAME, so it's easy to prioritize Google Cloud Build

[dfrankland]

Also, my test would fail without this 😝

[dfrankland]

Google Cloud Build doesn't have any built-in, default provided env vars. This seemed like the most unique and one that is always available (since this is how you trigger a build)

[trunk-io]

     

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[max-trunk]

IIUC the CIPlatform will only be anything other than Unknown if the current env var we're interrogating / trying to prioritize off of is a ci_platform_env_key (based on the CIPlatform::from() here) - which only Jenkins's ci_platform_env_key is BUILD_ID. So perhaps this isn't explicitly needed? Or I'm misinterpreting