Bump rack and activesupport

[navarone-feekery]

Resolves dependabot alerts: https://github.com/elastic/connectors-ruby/security/dependabot

[navarone-feekery]

@vidok this needs re-review as I had to fix the Gemfile.lock file

[github-actions[bot]]

💔 Failed to create backport PR(s)

The backport operation could not be completed due to the following error: You must specify a valid Github repository

You can specify it via either:

• Config file (recommended): ".backportrc.json". Read more: https://github.com/sqren/backport/blob/e119d71d6dc03cd061f6ad9b9a8b1cd995f98961/docs/configuration.md#project-config-backportrcjson
• CLI: "--upstream elastic/kibana"

The backport PRs will be merged automatically after passing CI.

To backport manually run: backport --pr 563 --autoMerge --autoMergeMethod squash