Use -trimpath on dist builds

[kevinmcconnell]

When building for release, the source paths are not useful in stacktraces. Adding -trimpath excludes them.

Before:

goroutine 1 [running]:
github.com/basecamp/thruster/internal.(*Service).Run(0xc00003df28)
	/home/kevin/work/basecamp/thruster/internal/service.go:42 +0x4d0
main.main()
	/home/kevin/work/basecamp/thruster/cmd/thrust/main.go:25 +0xa5

After:

goroutine 1 [running]:
github.com/basecamp/thruster/internal.(*Service).Run(0xc00003df28)
	github.com/basecamp/thruster/internal/service.go:42 +0x4d0
main.main()
	github.com/basecamp/thruster/cmd/thrust/main.go:25 +0xa5

Fixes #21.

[exegeteio]

Thank you, @kevinmcconnell. This looks much clearer. Sorry I couldn't get back to it quickly enough. =-[

[kevinmcconnell]

No worries, @exegeteio! Thanks for reporting it! 🙏