Feature Request: Support `-p` flag (test parallelism) like `go test`

[abdullayev13]

Hi! 👋

go test supports the -p flag to control the number of packages tested in parallel:

go test -p 1

I would like gotestsum to support the same flag:

gotestsum -p 1

This is especially useful when running tests that touch shared resources (DB, Redis, filesystem, etc.), in CI environments where limiting parallelism is important, or when test packages must run one-by-one (in my case).

Thanks for the great tool — this feature would help a lot with deterministic test execution. 🙏

[Tonkpils]

You can pass go test specific flags with gotestsum like this

gotestsum <gotestsum specific flags> -- <go test specific flags>

gotestsum --format short -- -parallel=1