add lib PCA9685 locally, because of warnings

test/test_main.cpp

@@ -13,12 +13,10 @@ void tearDown(void) {
     STR_TO_TEST = "";
 }
 
-
 void test_led_builtin_pin_number(void) {
     TEST_ASSERT_EQUAL(2, LED_BUILTIN);
 }
 
-
 void test_string_concat(void) {
     String hello = "Hello, ";
     String world = "world!";