tictactoe: added test case to check tied game

src/test/java/de/tims/tictactoe/GameLogicTest.java

@@ -234,6 +234,10 @@ class GameLogicTest {
 		    			Arguments.of("end of game with win for player 2", true, new char[][] 
 																				 {{'x', 'x', 'o'}, 
 																				  {'o', 'o', 'o'},
+																				  {'x', 'o', 'x'}}),
+		    			Arguments.of("check tied game", true, new char[][] 
+															 {{'x', 'x', 'o'}, 
+															  {'o', 'x', 'o'},
 															  {'x', 'o', 'x'}})
 		    		);
 	 }