package: updated readme for topics

README.md

@@ -94,7 +94,7 @@ A Raspberry Pi driver for MPU9250.  Ensure that the pigpio daemon is running bef
         The die temperature of the MPU9250 sensor.
 
 #### Services
-* **`imu/calibrate_gyroscope`** ([driver_mpu9250_msgs/calibrate_gyroscope](https://github.com/pcdangio/ros-driver_mpu9250/blob/master/driver_mpu9250_msgs/srv/calibrate_gyroscope.srv))
+* **`imu/calibrate_gyroscope`** ([sensor_msgs_ext/calibrate_gyroscope](https://github.com/pcdangio/ros-sensor_msgs_ext/blob/master/srv/calibrate_imu.srv))
         Calibrates the gyroscope by calculating and removing gyroscope bias. The bias is calculated by averaging gyroscope data over an averaging period.
 
 #### Parameters