Add CEL to K8sPSPCapabilities template

[maxsmythe]

What this PR does / why we need it:

Which issue(s) does this PR fix (optional, using fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when the PR gets merged):
Fixes #541

Special notes for your reviewer:

[JaydipGabani]

CEL looks good to me. We need to update template version and artifact-hub as well. make generate-all will do the job after updating template version. LGTM after these changes

[maxsmythe]

Bumped the minor version

[JaydipGabani]

LGTM

[JaydipGabani]

@maxsmythe should we use snake_case instead of camelCase for naming variables to be more consistent with variables in rego policies?

[maxsmythe]

@JaydipGabani

VAP appears to use camel case, and YAML params use camel case, so probably more consistent to stick with camel case.

Example from K8s documentation:

https://kubernetes.io/docs/reference/access-authn-authz/validating-admission-policy/#variable-composition

[stale]

This issue/PR has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[sozercan]

Thank you! LGTM