Fix duration response types

[JaniAnttonen]

Description

It seems that recently the return types of duration fields like token ttl have been changed in Hashicorp Vault. I was running tests against Vault v1.13.0 and encountered this error. Updated to v1.16.1 and the issue was still present.

After a while I noticed that others had encountered this too and described the error in detail, linking to a change inside Vault: hashicorp/vault#25510 (Don't know what this actually fixed, seems more likely that it created this issue)

Resolves #257
Resolves #249

How has this been tested?

I've used my fork in a private project in tests and these updates fixed the issue. The tests are running dockerized versions of Hashicorp Vault using testcontainers, and the issue is prevalent in both the default tag testcontainers uses hashicorp/vault:1.13.0 as well as the latest hashicorp/vault:1.16.1. This patch fixes the tests for both versions encountering the error json: cannot unmarshal number into Go struct field AppRoleWriteSecretIdResponse.data.secret_id_ttl of type string.

Also, creators of cert-manager/cert-manager#6601 might be interested in this update since it removes their need for using raw workarounds.

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[guru-jani]

Read and agreed to the CLA with both linked contributor accounts, but it still seems to hang around :O

[barisere]

Thanks for submitting this fix, @JaniAnttonen. I'm blocked by this, so I'll use your commit for now until this PR is merged.

[ArcRiiad]

Any update on this PR?

[WqyJh]

Same problem

[WqyJh]

This PR contains a huge amount of unnecessary changes, please consider to cherry-pick this commit WqyJh@cd7bc62 instead. @JaniAnttonen