Breaking change notes related to cidr (#421)

See npgsql/npgsql#5891
See npgsql/efcore.pg#3321

Author: roji

conceptual/EFCore.PG/release-notes/10.0.md

@@ -144,6 +144,8 @@ See the [10.0.0 milestone](https://github.com/npgsql/efcore.pg/milestone/68?clos
 
 ## Breaking changes
 
+* `EF.Functions.Network()` and `EF.Functions.Merge()` have been changed to return the new .NET [`IPNetwork`](https://learn.microsoft.com/dotnet/api/system.net.ipnetwork) instead of the obsolete `NpgsqlCidr`. The new `IPNetwork` type works with all other functions as well (but no breaking changes were necessary).
+
 ## Contributors
 
 To be completed.

conceptual/Npgsql/release-notes/10.0.md

@@ -0,0 +1,7 @@
+# Npgsql 10.0 Release Notes
+
+Npgsql version 10.0 is now in development, preview versions are available on [nuget.org](https://www.nuget.org/packages/Npgsql).
+
+## Breaking changes
+
+* The PostgreSQL network type `cidr` is now scaffolded to the new .NET [`IPNetwork`](https://learn.microsoft.com/dotnet/api/system.net.ipnetwork) type. The older Npgsql representation for `cidr` - the `NpgsqlCidr` type - has been obsoleted and will be removed in a future release.