Feature: Add support for TopologySpreadConstraint and PodDistruptionBudget

[pjaak]

Requirements

• [x] I have added test coverage for new or changed functionality
• [x] I have followed the repository's pull request submission guidelines
• [x] I have validated my changes against all supported platform versions

Related issues https://github.com/launchdarkly/ld-relay-helm/issues/42 https://github.com/launchdarkly/ld-relay-helm/issues/43

Describe the solution you've provided

Added an option to enable a PodDistruptionBudget for the relay deployment. In the values file you can specify a maxUnavailable or a minAvailable, but can't specify both. If both are specified the maxUnavailable takes precedence. If you enabled the PDB but don't specify any max or min values then minAvailable will be set with a value of 0. Tests have been added to cover these cases

Adds an option to specify multiple TopologySpreadConstraints in the values file which will be used by the relay deployment. If you don't specify LabelSelector in the values it will use the default selectorLabels from the template which is recommended.

Additional context

I had to update some of the go packages and dependencies to support the policy/v1 for the PDB. Can confirm all tests pass successfully. Also had to update some of the tests in the deployment.

[LiamStorkey]

Great idea! - LGMT

[louis-launchdarkly]

Hello @pjaak, thank you for the contribution. When the engineer is available, we will review this and make progress on this.

[pjaak]

Thank you for your contribution! Overall this looks good to me. I had a couple of tweaks and questions I'd like us to discuss, so let me know your thoughts. Thanks again!!

Thanks for the feedback @keelerm84, all makes sense to me. Let me implement the changes and push them up.

[pjaak]

I have pushed some latest changes and left some comments.

Thanks! :D

[keelerm84]

Released in 2.4.0