Update vault sdk

[luispresuelVenafi]

• Resolves https://github.com/Venafi/vault-pki-backend-venafi/issues/121

• Cleaned some old dependency with VCert 3.x

• Upgrades Golang to be mandatory on 1.21 on go.mod file

• Upgrades libraries for VC-26776

• Fixes bug that broke proactive token refresh:

$ vault write venafi-pki/issue/tpp-refresh common_name="dffsdsd.venafi.example"
Error writing data to venafi-pki/issue/tpp-refresh: Error making API request.

URL: PUT http://tpp.venafi.example:8200/v1/venafi-pki/issue/tpp-refresh
Code: 500. Errors:

* 1 error occurred:
    * unexpected status code on TPP Authorize. Status: 400 Bad Request

After exposing the error while debugging:

{"error":"unauthorized_client","error_description":"The client_id value being requested with the refresh token does not match the client_id of the access token making the call."}

that was introduced here: https://github.com/Venafi/vault-pki-backend-venafi/pull/108

[rvelaVenafi]

arent you upgrading vcert dependency to 5.X as well?

[luispresuelVenafi]

Didn't mean to do it at all, but for upgrading other libraries I ended doing it in this PR: https://github.com/Venafi/vault-pki-backend-venafi/pull/130