Deprecate c headers (#25)

Related to this [pull
request](ros2/geometry2#720) in `geometry2` in
which we deprecated the `.h` style headers in favor of `.hpp`.

---------

Signed-off-by: CursedRock17 <[email protected]>

Author: CursedRock17

imu_transformer/include/imu_transformer/tf2_sensor_msgs.h

@@ -32,7 +32,7 @@
 #ifndef TF2_SENSOR_MSGS_H
 #define TF2_SENSOR_MSGS_H
 
-#include <tf2/convert.h>
+#include <tf2/convert.hpp>
 #include <sensor_msgs/msg/imu.hpp>
 #include <sensor_msgs/msg/magnetic_field.hpp>
 #include <Eigen/Eigen>

imu_transformer/test/test_imu_transforms.cpp

@@ -9,7 +9,7 @@
 #include "gtest/gtest.h"
 
 
-#include <tf2/LinearMath/Quaternion.h>
+#include <tf2/LinearMath/Quaternion.hpp>
 #include <tf2_geometry_msgs/tf2_geometry_msgs.hpp>
 
 #include <Eigen/Eigen>