circleci: add go1.21, go1.22, go1.23, and update golangci-lint to v1.60.3

[thaJeztah]

No description provided.

[thaJeztah]

FWIW, one of the linters is deprecated;

WARN The linter 'exportloopref' is deprecated (since v1.60.2) due to: Since Go1.22 (loopvar) this linter is no longer relevant. Replaced by copyloopvar.

However changing it to the replacement doesn't help much, because that looks at the go version in go.mod;

WARN [linters_context] copyloopvar: this linter is disabled because the Go version (1.17) of your project is lower than Go 1.22

So I kept the deprecated (but currently still functional) one for now.

[dnephin]

Thank you! I pushed a commit to remove go1.18 and go1.19. I generally remove older versions when I add new ones, and keep it to 4 (or fewer) versions being tested.