Release v0.48.0

Changed

• Updated github.com/lucas-clemente/quic-go@v0.31.1 dependency to github.com/quic-go/quic-go@v0.32.0

Fixed

• Requirements for domain names in domain-specific upstream configurations have been relaxed to meet those from RFC 3696.

Removed

• Go 1.18 support, as it has reached end of life.