Update dependencies to address security alerts

[arybolovlev]

Description

This PR includes the following changes:

• bump Kubernetes dependencies from x.25.5 to x.25.11.
• bump Golang version from 1.19 to 1.20.
• rid of the vendor/ folder.

The main reason for bumping Kubernetes dependencies is to address security alerts, that is why I bumped it within the same minor release(that is why there is no change log). There are some changes in x.27 that would require small changes in the code. It is better to have a different PR to update all dependencies including Kubernetes ones.

Acceptance tests

• Have you added an acceptance test for the functionality being added?
• Have you run the acceptance tests on this branch?

Output from acceptance testing:

NONE.

Release Note

Release note for [CHANGELOG](https://github.com/hashicorp/terraform-provider-
kubernetes/blob/main/CHANGELOG.md):

NONE.

References

N/A.

Community Note

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