chore(deps): Upgrade Ruby version to 3.1.4 (#17722)

Seems to remove flakiness from component docs check so I removed the
retry.

I manually verified the other Ruby scripts still run on Ruby 3.

I added a `.ruby-version` file to ensure CI and local Ruby use uses the
same version. 3.1.4 should
already be installed on the runner image per
https://github.com/actions/runner-images/blob/ubuntu20/20230611.1/images/linux/Ubuntu2004-Readme.md.

Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

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Signed-off-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>