OPS-5860 Update k8s client tools and cdk8s imports to v1.31.x

[michelesr]

Describe your changes

Update clients tools to 1.31

Checklist before requesting a review

• I have performed a self-review of my code
• I have updated the Readme / docs
• If this is a breaking change, I have discussed the roll-out and roll-back plan with the team(s) and I have provided detailed instructions
• If it is a core feature, I have added thorough tests

[ruthwells]

I'm not familiar with the typeguard stuff, so can't really comment on that but other stuff looks reasonable.