CA Pinning improvements
- Add an option to disable CA certificate pinning
- Add CA bundle version and pinning status to the user agent string
- Add appendToUserAgent() method to Client class
- Prevent OS certificate store fallback when CA pinning is enabled
Breaking Changes
DuoAPI\FileRequester class has been removed. This was never used by default. Users who directly constructed and injected this class will need to switch to CurlRequester.