Update includes to to be relative to src directory

Don't use relative imports like `../foo.h` as those depend on the
relative position of both files. Rather than that use imports relative
to the `src` directory, which explicitly is part of the include
directories.

src/drivers/Hrs3300.cpp

@@ -6,7 +6,7 @@
 
 #include <algorithm>
 #include <nrf_gpio.h>
-#include "Hrs3300.h"
+#include "drivers/Hrs3300.h"
 
 #include <FreeRTOS.h>
 #include <task.h>