Use Go 1.23 default GODEBUG

[jrick]

Removes the following compatibility flags when building the "go 1.22" module with Go 1.23:

build	DefaultGODEBUG=asynctimerchan=1,gotypesalias=0,httpservecontentkeepheaders=1,tls3des=1,tlskyber=0,x509keypairleaf=0,x509negativeserial=1

[davecgh]

Won't this cause anyone who imports it to also be forced into incompatible behavior that they might rely on?

[jrick]

can't import a main package

[davecgh]

Oh, right. I missed it was for main.