fix: explicitly set client encoding on PG connection

Refs #2465

Author: ansgarbecker

source/dbconnection.pas

@@ -2807,6 +2807,7 @@ procedure TPgConnection.SetActive(Value: Boolean);
       raise EDbError.Create(Error, LastErrorCode, ErrorHint);
     end;
     FActive := True;
+    CharacterSet := 'UTF8';
     FServerDateTimeOnStartup := GetVar('SELECT ' + FSqlProvider.GetSql(qFuncNow));
     FServerVersionUntouched := GetVar('SELECT VERSION()');
     FConnectionStarted := GetTickCount64 div 1000;
@@ -4463,7 +4464,7 @@ procedure TMySQLConnection.SetCharacterSet(CharsetName: String);
 procedure TPGConnection.SetCharacterSet(CharsetName: String);
 begin
   // See issue #22
-  Query('SET CLIENT_ENCODING TO ' + EscapeString('UTF8'));
+  Query('SET CLIENT_ENCODING TO ' + EscapeString(CharsetName));
 end;