What would you like to be added?

Kubernetes is updating to Golang 1.21: kubernetes/kubernetes#118996

This issue would bring etcd to be in line with Kubernetes and would keep etcd main at the latest Golang version.

In Go 1.21, there are two noteworthy deprecations:

• math/rand.Read
• math/rand.Seed

Etcd, bbolt, and raft do not use these so this is a simple bump.

Consider updating:

• etcd/main Update to go1.21 #16594
• etcd/release-3.5
• etcd/release-3.4
• bbolt/master Update to go1.21.1 bbolt#566
• raft/main Update to go1.21.1 raft#101

Why is this needed?

Keep etcd in line with Kubernetes Go version.