Upgrade default etcd version to 3.5.17

[GrahamCampbell]

This PR upgrades the default etcd version to 3.5.17.

Corresponding PR on vitess: vitessio/vitess#17653

[GuptaManan100]

The DCO check seems to be failing 😕. Did you add the -s flag while committing?

[GrahamCampbell]

Made the commit from the GitHub webapp. 🤷

[frouioui]

The etcd version should be changed everywhere both in vitess and vtop.

[frouioui]

Have you tested upgrade paths with a vitess cluster on K8S using the previous etcd version, upgrading to the other etcd version? Same thing with downgrades.

[GrahamCampbell]

Not tested. PR based on #447.

[frouioui]

In this case we need to do #447 (comment) too :)

[GrahamCampbell]

Re-pushed with a signed off commit.

[frouioui]

LGTM. Can you modify the release notes summary for the next release (2.15.0) to include a note on how to proceed with this newer etcd version, #447 (comment).

[frouioui]

Let's open a PR on vitess to make the etcd version match too please, we use v3.3.10 in the tests. We also use the ETCD_VER env variable in several places, in the vitess repo, which should be set to the same version as here.

For #654 (review)