Bump dnspython from 2.4.2 to 2.6.1 (#2264)

* Bump dnspython from 2.4.2 to 2.6.1

Bumps [dnspython](https://github.com/rthalley/dnspython) from 2.4.2 to 2.6.1.
- [Release notes](https://github.com/rthalley/dnspython/releases)
- [Changelog](https://github.com/rthalley/dnspython/blob/main/doc/whatsnew.rst)
- [Commits](https://github.com/rthalley/dnspython/compare/v2.4.2...v2.6.1)

---
updated-dependencies:
- dependency-name: dnspython
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update dnspython==2.6.1

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: JonnyWong16 <9099342+JonnyWong16@users.noreply.github.com>

[skip ci]

lib/dns/_trio_backend.py

@@ -8,9 +8,13 @@ import trio
 import trio.socket  # type: ignore
 
 import dns._asyncbackend
+import dns._features
 import dns.exception
 import dns.inet
 
+if not dns._features.have("trio"):
+    raise ImportError("trio not found or too old")
+
 
 def _maybe_timeout(timeout):
     if timeout is not None:
@@ -95,7 +99,7 @@ class StreamSocket(dns._asyncbackend.StreamSocket):
             raise NotImplementedError
 
 
-try:
+if dns._features.have("doh"):
     import httpcore
     import httpcore._backends.trio
     import httpx
@@ -177,7 +181,7 @@ try:
                 resolver, local_port, bootstrap_address, family
             )
 
-except ImportError:
+else:
     _HTTPTransport = dns._asyncbackend.NullTransport  # type: ignore