Update module github.com/banzaicloud/bank-vaults/pkg/sdk to v1.15.3

[simu]

We can't update to the actual v1.15.3, go get -u fails with the following error:

$ go get -u github.com/banzaicloud/bank-vaults/pkg/sdk@v1.15.3
go: module github.com/banzaicloud/bank-vaults@v1.15.3 found, but does not contain package github.com/banzaicloud/bank-vaults/pkg/sdk

However, go get -u github.com/banzaicloud/bank-vaults/pkg/sdk@1.15.3 results in the diff shown in this PR.

Replaces #230

Checklist

• [x] Keep pull requests small so they can be easily reviewed.
• [x] Categorize the PR by setting a good title and adding one of the labels: bug, enhancement, documentation, change, breaking, dependency as they show up in the changelog
• [x] Link this PR to related issues.

[simu]

You can't update to v1.15.3 as the sdk uses a separate go.mod and is versioned differently with some git tag magic.

I see, looking at the diff since the pkg/sdk/v0.8.3 tag, there don't seem to be any relevant changes: https://github.com/banzaicloud/bank-vaults/compare/385412dfd0fed2c9f4e47b2f4265db8a80c6d0c6..main, so I think we can just take the Renovate PR instead of this one.

[simu]

Closing in favor of #230