Make compatible with Go 1.21 (update quic-go)

[eclipseo]

Go 1.21 is around the corner and we already have the rc3 in Fedora Rawhide. It would be nice to update quic-go to at least v0.37.4 https://github.com/quic-go/quic-go/releases/tag/v0.37.4

Thank you.

[AaronH88]

Thanks for this issue and PR @eclipseo .
The quic-go 0.37 release not only supports Go 1.21 but it removed backward compatibility for any Go version less than 1.20.
As a result, this update will need to be carefully managed so as not to break any application build upon receptor.

Once I have confirmation that dropping support for Go 1.19 is ok I will merge.

Thanks once again.
CC @TheRealHaoLiu @shanemcd @fosterseth

[AaronH88]

I just confirmed that receptor build uses go from RHEL and the latest released version is 1.19 right now. looks like 1.20 will be released in RHEL 8.9/9.3 mid-November. We will not be able to drop support for GO 1.19 until then.