pg-dump-anon: use latest postgresql available

While reviewing #352966 I noticed that the pg_anonymizer test fails for
postgresql 17. The reason for that is that `pkgs.postgresql` is v16 and
using its psql to connect against a v17 database doesn't work.

I decided that we'll just use the latest available package in here. I
don't want to introduce another attribute (`postgresql_latest`), if
there are too many instances of that we're blocked on adding new
postgresql majors directly to master again which is the current status
quo. With the test rework in #352966 it's also way easier to catch this.

pkgs/by-name/pg/pg-dump-anon/package.nix

@@ -1,4 +1,4 @@
-{ lib, fetchFromGitLab, buildGoModule, nixosTests, postgresql, makeWrapper }:
+{ lib, fetchFromGitLab, buildGoModule, nixosTests, postgresql_17, makeWrapper }:
 
 buildGoModule rec {
   pname = "pg-dump-anon";
@@ -19,7 +19,7 @@ buildGoModule rec {
   nativeBuildInputs = [ makeWrapper ];
   postInstall = ''
     wrapProgram $out/bin/pg_dump_anon \
-      --prefix PATH : ${lib.makeBinPath [ postgresql ]}
+      --prefix PATH : ${lib.makeBinPath [ postgresql_17 ]}
   '';
 
   meta = with lib; {