BREAKING CHANGE (behavior): Modify caching to only attempt to update the response cache if a 2xx response code is received from GitHub

[daverant]

Resolves #2876

Apologies if I've filed a bug when it should come under feature/enhancement!
I couldn't find any docs on response caching, but happy to update them if there are any.

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Before the change?

• If the CachingHttpClient received a non-200 and non-304 response from GitHub, it still attempts to update the underlying response cache, resulting in a higher number of subsequent cache misses if IResponseCache implementations don't guard for it themselves.

After the change?

• Only attempts to update the response cache if a 2xx response code is received from GitHub.

Pull request checklist

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)

Does this introduce a breaking change?

• I don't believe this is classed as a breaking change, but it is a change in behaviour that could impact users who rely on it calling the response cache for non-200 responses.

• Yes
• No

[nickfloyd]

I am going to classify this as a breaking change due to the change in behavior in potential expectations that you point out. This is a great change, thank you for doing it! ❤️