feat(install): plugins support APOLLO_ROVER_DOWNLOAD_HOST

[LongLiveCHIEF]

This PR adds the ability for rover plugins to be downloaded through a user-designated mirror/proxy of rover.apollo.dev. related #1638, and possibly related: #1253 #1583

Documentation was updated for the npm section, although this variable is respected for plugin downloads regardless of installation method of rover, so additional documentation may be needed at a higher level to address the proxy/mirror pattern of managing rover installations.

[EverlastingBugstopper]

🥳 This is why I love open source! Thanks for the contribution and look forward to continuing to improve the project with you

[EverlastingBugstopper]

updating my review to request changes as the PR does not compile due to the s/$/& suggestion above. I'd push the commit myself but since it's a fork I am (reasonably) unable to.

[EverlastingBugstopper]

also needs a cargo fmt --all ran on the codebase

[LongLiveCHIEF]

Until i tried to run the cargo xtask lint locally myself just now, I had never heard of volta. Kinda looks like a neat tool, and I will have to see if that has configurable downloads now 🤣

[Meschreiber]

Just a small suggestion to align to our content style guidelines. Thanks for documenting this!

[LongLiveCHIEF]

Do we know when this will be included in a release? It's basically unusable until then since it's a binary 😃

[EverlastingBugstopper]

Sure - the next release is scheduled for next week. If you desperately need this before then, I recommend building from source. Cloning and running cargo xtask package will build a release binary for you using the same process as our CI and dump a tarball in ./artifacts (though note this won't work for our MacOS builds as they are notarized and require secrets that you won't have access to - in that case just run cargo build --release -p rover && ./target/release/rover install to run the install step).

[LongLiveCHIEF]

Sure - the next release is scheduled for next week. If you desperately need this before then, I recommend building from source. Cloning and running cargo xtask package will build a release binary for you using the same process as our CI and dump a tarball in ./artifacts (though note this won't work for our MacOS builds as they are notarized and require secrets that you won't have access to - in that case just run cargo build --release -p rover && ./target/release/rover install to run the install step).

Yeah, gotta love Mac's "can't scan this application so we've decided you can't use it" level of harrassment for developers. 🤣

For now, I've built a cargo binary for mac locally and will see if we've got any issues from that ahead of the next release. Does that have a specific date yet, or is it just a milestone with a burn down chart of issues?