* Native Login method, userpass and approle interfaces to implement it
* Add AWS auth interface for Login, unexported struct fields for now
* Add Kubernetes client login
* Add changelog
* Add a test for approle client login
* Return errors from LoginOptions, use limited reader for secret ID
* Fix auth comment length
* Return actual type not interface, check for client token in tests
* Require specification of secret ID location using SecretID struct as AppRole arg
* Allow password from env, file, or plaintext
* Add flexibility in how to fetch k8s service token, but still with default
* Avoid passing strings that need to be validated by just having different login options
* Try a couple real tests with approle and userpass login
* Fix method name in comment
* Add context to Login methods, remove comments about certain sources being inherently insecure
* Perform read of secret ID at login time
* Read password from file at login time
* Pass context in integ tests
* Read env var values in at login time, add extra tests
* Update api version
* Revert "Update api version"
This reverts commit 1ef3949497dcf878c47e0e5ffcbc8cac1c3c1679.
* Update api version in all go.mod files
