Upgrade void to rails 7

[BSick7]

During SOC2 readiness, a vulnerability was flagged in a rails library. The only way to remediate is to upgrade to rails 7.

Issues

• Authentication fails, user is logged out. When attempting to log in, user gets HTTP 500 on oauth redirect from github.
  • no implicit conversion of String into Integer
  • uninitialized constant PosthogEvents::PostHog (PostHog::Client.new(...)