test: split TestGetVersion; remove toolchain

[alexandear]

The PR splits TestGetVersion into two: TestGetDevelopmentVersion and TestGetReleaseVersion.

TestGetDevelopmentVersion slightly differs for Go 1.24 and Go 1.23. So, I split it into:

• main_pre_go1.24_test.go: //go:build !go1.24 means Go 1.23 and below.
• main_go1.24_test.go: //go:build go1.24 means Go 1.24 and above.

Also, the PR removes unnecessary requirement of using the latest Go during development (toolchain in go.mod) and drops 1.22 in CI (because we support only Go 1.23+).

Inspired by #1302.

[ccoVeille]

🎨

I wouldn't prefix them with main_

It leads to some confusions with possible build tag available via file suffix. Like main_386_test.go

I initially thought main_test.go file wasn't used.

Maybe you could rename these files with a common prefix that is not main_

[alexandear]

Renamed main_go123_test.go to main_pre_go124_test.go (similar to pre_go120.go https://github.com/golang/sync/tree/10739b037d369c748d671b216356d7e04ce68da1/errgroup)

The prefix main_ is expected by Go convention https://pkg.go.dev/cmd/go#hdr-Test_packages:

• main_test.go contains tests for main.go

• main_pre_go124_test.go contains tests for main.go, but only for Go 1.23 and below

• main_go124_test.go contains tests for main.go, but only for Go 1.24 and above