Update changelog.

Changelog.md

@@ -13,6 +13,10 @@ New
 * Added support for `NAPTR` record type. ([#427] by [@weilence])
 * Added initial fuzz testing support for some types via a new `arbitrary`
   feature (not enabled by default). ([#441])
+* Added `StubResolver::add_connection()` to allow adding a connection to the
+  running resolver. In combination with `ResolvConf::new()` this can also be
+  used to control the connections made when testing code that uses the stub
+  resolver. ([#440])
 
 Bug fixes
 
@@ -39,6 +43,7 @@ Other changes
 [#417]: https://github.com/NLnetLabs/domain/pull/417
 [#421]: https://github.com/NLnetLabs/domain/pull/421
 [#427]: https://github.com/NLnetLabs/domain/pull/427
+[#440]: https://github.com/NLnetLabs/domain/pull/440
 [#441]: https://github.com/NLnetLabs/domain/pull/441
 [@weilence]: https://github.com/weilence