change token type ttl to string

[nefeldt]

https://developer.hashicorp.com/vault/api-docs/auth/token#create-token
ttl should be string not int

ttl (string: "") - The TTL period of the token, provided as "1h", where hour is the largest suffix. If not provided, the token is valid for the default lease TTL, or indefinitely if the root policy is used.

[Copilot]

Pull Request Overview

This PR aligns the TTL field type in the authentication token creation request with the HashiCorp Vault API specification, which requires TTL to be a string (e.g., "1h") rather than an integer.

• Changes the TTL field type from int to string in the AuthCreateTokenRequest struct

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