Add CI to run tests and benchmarks automatically

[kkebo]

A CI pipeline should contain:

• swift test
• swift package benchmark baseline check main pull_request
  • https://swiftpackageindex.com/ordo-one/package-benchmark/1.6.5/documentation/benchmark/comparingbenchmarksci

[kkebo]

https://swiftpackageindex.com/ordo-one/package-benchmark/1.7.0/documentation/benchmark/comparingbenchmarksci

For reproducible and good comparable results, it is highly recommended to set up a private GitHub runner on a machine dedicated to performance benchmark runs.

I can't prepare a private runner, so I decided not to add a CI job for benchmarking.