update ci workflow

[kturney]

Summary

Revamps and fixes CI workflow.

Updates

• migrated rust-toolchain to newer rust-toolchain.toml
• utilized the rustup included in ubuntu-latest to install the toolchain specified in rust-toolchain.toml
• based Rust CI setup on the rust-analyzer CI workflow
  • added caching
  • added faster build ordering
  • added separation of test build and test execution
  • disabled incremental builds in CI
• used available actions to install additional languages instead of leaning on apt-get directly

Potential shortcomings

• had to use newer Swift than readme says serge-reflection supports (5.7 instead of 5.3) due to gpg issues with older Swift versions
• had to add an include for std::numeric_limits to fix cpp tests, matching fix found here. I'm not sure if that is considered a breaking change.

Misc

Warnings during tests indicate that .Net@2.1 is no longer supported. We could use this opportunity to bump the minimum support versions of different supported runtimes.

[ma2bd]

@kturney Thanks for the PR. This looks great! My only ask is that we keep using the pinned version of Rust (aka the one from rust-toolchain) in CI. Otherwise, I believe CI may break (typically clippy) whenever ubuntu-latest changes.

[kturney]

Hi @ma2bd, thanks for the quick review! Since the rust-toolchain.toml is there, CI is currently pinned to using 1.60.0 for everything. And it's my understanding that will only change if we update the toolchain in the rust-toolchain.toml. Is that not correct?

Are you wanting me to change every use of cargo to cargo +1.60.0 to be extra certain?