update drone to run with pi user

.drone.yml

@@ -11,8 +11,6 @@ steps:
 - name: static check
   commands:
   - cd gateway
-  - whoami
-  - export
   - pio check -e pro-mini
   when:
     target:
@@ -31,10 +29,10 @@ steps:
 - name: upload firmware
   commands:
   - cd gateway
-  - service ser2net stop
+  - sudo service ser2net stop
   - pio run -e pro-mini
   - echo 'reset' > /dev/ttyUSB0; sleep 1s; avrdude -patmega328p -carduino -P/dev/ttyUSB0 -b115200 -D -Uflash:w:.pio/build/pro-mini/firmware.hex:i -v
-  - service ser2net start
+  - sudo service ser2net start
   when:
     target:
     - production