Truststore is a library which exposes native system certificate stores (ie
"trust stores") through an ssl.SSLContext-like API. This means that Python
applications no longer need to rely on certifi as a root certificate store.
Native system certificate stores have many helpful features compared to a
static certificate bundle like certifi:

* Automatically update certificates as new CAs are created and removed
* Fetch missing intermediate certificates
* Check certificates against certificate revocation lists (CRLs) to avoid
  monster-in-the-middle (MITM) attacks
* Managed per-system rather than per-application by a operations/IT team
* PyPI is no longer a CA distribution channel