Set supported SSH algorithms and require Go 1.23

This fixes SSH connections for the fleeting plugin.

This needs the Labkit update: gitlab-org/labkit!207 (merged)

Relates to gitlab-org/gitlab-runner#38963 (closed)

This is the FIPS job demonstrating the failure before this fix: https://gitlab.com/gitlab-org/fleeting/fleeting/-/jobs/10998628143