Add changelog entry

Author: oschwald

CHANGELOG.md

@@ -1,5 +1,24 @@
 # Change Log #
 
+## 0.23.0 - 2022-04-03
+
+* Added `lookup_prefix` to return the prefix length for the network
+  associated with the IP address. Pull request by  Marek Vavruša.
+  GitHub #26.
+
+## 0.22.0 - 2022-03-23
+
+* A `within` method has been added to the reader to allow iterating
+  over all records in the database. Pull request by Ross McFarland.
+  Github #50.
+* Database structs in `maxminddb::geoip2` have been updated. Most
+  noticeably, an `Enterprise` struct has been added and the `model`
+  module has been replaced by `city` and `country` modules. Also,
+  several missing fields have been added.
+* `Mmap` is now re-exported for convenience. Pull request by zhuhaow.
+  GitHub #54.
+* Upgraded memmap2 dependency.
+
 ## 0.21.0 - 2021-07-20
 
 * Reduce the amount of code generated by shrinking generic methods.