Adds uint48 methods for cryptobyte.Builder and cryptobyte.String. Supporting 48-bit unsigned integers is useful for working with protocols that use them for sequence numbers, such as DTLS. Fixes golang/go#61275 Change-Id: Ibe49422d37644b9212b28b123dc5e01850f7b05b GitHub-Last-Rev: 11b388c240109c8f4ac23880645c901ce6d2f093 GitHub-Pull-Request: golang/crypto#265 Reviewed-on: https://go-review.googlesource.com/c/crypto/+/508675 Reviewed-by: Roland Shoemaker <roland@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: qiulaidongfeng <2645477756@qq.com> Run-TryBot: Roland Shoemaker <roland@golang.org> Auto-Submit: Roland Shoemaker <roland@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org>