Invalidate the buildkit cache when the content of a build secret changes

[pchico83]

Is your feature request related to a problem? Please describe.
By default, buildkit doesn't invalidate the content of the build cache when using build secrets, and the content of the secret changes.
This is creating friction in our users, because OKTETO_NAMESPACE is commonly part of the secret (and then, we are reusing builds between namespaces). Or if an admin updates a build secret value, it's hard to understand why the build is caching the previous build.

Describe the solution you'd like
In validate the build cache if the content of the secret changes.
One option to do this is to use as the id of the mount syntax a hash generated from the content of the secret.

[github-actions]

This issue is stale because it has been open for 60 days with no activity. Comment on this issue or it will be closed in 7 days

[github-actions]

This issue is stale because it has been open for 60 days with no activity. Comment on this issue or it will be closed in 7 days