[ci] lock utest version to pre-2.0

tests/RunCi.hx

@@ -46,7 +46,7 @@ class RunCi {
 			infoMsg('test $test');
 			try {
 				changeDirectory(unitDir);
-				haxelibInstallGit("haxe-utest", "utest", "master", "--always");
+				haxelibInstallGit("haxe-utest", "utest", "a94f8812e8786f2b5fec52ce9f26927591d26327", "--always");
 
 				var args = switch (ci) {
 					case null: