This PR removes go-sumtype from cloudflared's build processes.
The value we see from analysing exhaustive match patterns in go is minimal (we can do this in code reviews) compared to using a tool that is unmaintained and (now broken) in Go 1.18.
We'd already been using the patched version here: https://github.com/sudarshan-reddy/go-sumtype because the original is broken for go tools > 1.16
Sudarsan Reddy
Areg Harutyunyan