Underlying API update
- It looks like Google released a stable API version for the Secret Manager API, though there were no changes that impacted this library. I went ahead and moved to it. This moves from the v1beta1 API to the v1 api for Secret Manager.
- Google updated the docs to say secret names are limited to 255 chars, which I've documented and now trim secret names to that length.
- Did some minor lint cleanup.