Update default Spinnaker installation to 1.33.0 and hal image to 1.51.0

[ranesagar]

The default version this helm chart installs is quite old. Please update the default Spinnaker installation to 1.33.0 and default hal image to 1.51.0.

We've have been running these versions on production with multiple deployments per day and these versions have been quite stable.

[ranesagar]

Hello @keerthibingi / @ksrinimba - can you please review #56 which addresses this issue?

[keerthibingi]

Approved and merged the PR.
Thank you @ranesagar