Re-generate README

README.md

@@ -15,7 +15,8 @@ This crate lets you connect to and interact with servers that implement the IMAP
 3501](https://tools.ietf.org/html/rfc3501) and various extensions). After authenticating with
 the server, IMAP lets you list, fetch, and search for e-mails, as well as monitor mailboxes for
 changes. It supports at least the latest three stable Rust releases (possibly even older ones;
-check the [CI results](https://travis-ci.com/jonhoo/rust-imap)).
+check the [CI
+results](https://dev.azure.com/jonhoo/jonhoo/_build/latest?definitionId=11&branchName=master)).
 
 To connect, use the [`connect`] function. This gives you an unauthenticated [`Client`]. You can
 then use [`Client::login`] or [`Client::authenticate`] to perform username/password or
@@ -71,6 +72,22 @@ fn fetch_inbox_top() -> imap::error::Result<Option<String>> {
 }
 ```
 
+### Opting out of `native_tls`
+
+For situations where using openssl becomes problematic, you can disable the
+default feature which provides integration with the `native_tls` crate. One major
+reason you might want to do this is cross-compiling. To opt out of native_tls, add
+this to your Cargo.toml file:
+
+```toml
+[dependencies.imap]
+version = "<some version>"
+default-features = false
+```
+
+Even without `native_tls`, you can still use TLS by leveraging the pure Rust `rustls`
+crate. See the example/rustls.rs file for a working example.
+
 ## Running the test suite
 
 To run the integration tests, you need to have [GreenMail