Bump dnspython from 2.3.0 to 2.4.2 (#2123)

* Bump dnspython from 2.3.0 to 2.4.2

Bumps [dnspython](https://github.com/rthalley/dnspython) from 2.3.0 to 2.4.2.
- [Release notes](https://github.com/rthalley/dnspython/releases)
- [Changelog](https://github.com/rthalley/dnspython/blob/master/doc/whatsnew.rst)
- [Commits](https://github.com/rthalley/dnspython/compare/v2.3.0...v2.4.2)

---
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==2.4.2

---------

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/inet.py

@@ -17,14 +17,12 @@
 
 """Generic Internet address helper functions."""
 
-from typing import Any, Optional, Tuple
-
 import socket
+from typing import Any, Optional, Tuple
 
 import dns.ipv4
 import dns.ipv6
 
-
 # We assume that AF_INET and AF_INET6 are always defined.  We keep
 # these here for the benefit of any old code (unlikely though that
 # is!).
@@ -171,3 +169,12 @@ def low_level_address_tuple(
             return tup
     else:
         raise NotImplementedError(f"unknown address family {af}")
+
+
+def any_for_af(af):
+    """Return the 'any' address for the specified address family."""
+    if af == socket.AF_INET:
+        return "0.0.0.0"
+    elif af == socket.AF_INET6:
+        return "::"
+    raise NotImplementedError(f"unknown address family {af}")