deps: upgrade raft from v1.6.1 -> v1.7.1

[schmichael]

The major change between Raft v1.6 -> v1.7 was the introduction of the Prevote feature. Before Prevote, when a partitioned node rejoins a cluster it may cause an election even if the cluster was stable. Prevote can avoid this useless election so reintroducing partitioned servers to an otherwise stable cluster becomes seamless.

Full details: hashicorp/raft#530

In #20335 we discussed whether or not to add a configuration option to disable prevote in case bugs were discovered. While bugs have been found (hence the v1.7.1 version as opposed to v1.7.0), I'm choosing to follow Vault's lead of straightfordwardly bumping the raft dependency: hashicorp/vault#27605 and hashicorp/vault#28218

[jrasell]

LGTM 🥳

[pkazmierczak]

LGTM and a welcome change for sure, but I'd love to see this tested in nomad-bench against raft 1.6 to see if there aren't any performance regressions.

[tgross]

LGTM

As much as a functional change like this is scary to backport, we should do so anyways. There aren't LTS branches for Raft so if there's a security bug in the library in the future we'd end up having to backport anyways.

[schmichael]

As much as a functional change like this is scary to backport, we should do so anyways. There aren't LTS branches for Raft so if there's a security bug in the library in the future we'd end up having to backport anyways.

Vault does not have plans to backport Raft 1.7.1, so I would like to match their behavior. If a Raft CVE or critical-bug fix lands in Raft 1.7.x, we will backport Raft 1.7.x for that fix. Hopefully that will give PreVote a bit more time testing in the wild, although we have no reason to suspect issues.

LGTM and a welcome change for sure, but I'd love to see this tested in nomad-bench against raft 1.6 to see if there aren't any performance regressions.

Created an internal task for me to do this post-merge: https://hashicorp.atlassian.net/browse/NET-11147