Fix incorrect file extension in package file

Author: sebromero

package.json

@@ -2,7 +2,7 @@
   "urls": [
     ["arduino/__init__.py", "github:arduino/arduino-runtime-mpy/arduino/__init__.py"],
     ["arduino/arduino.py", "github:arduino/arduino-runtime-mpy/arduino/arduino.py"],
-    ["arduino/template.py", "github:arduino/arduino-runtime-mpy/arduino/template.py"]
+    ["arduino/template.tpl", "github:arduino/arduino-runtime-mpy/arduino/template.tpl"]
   ],
   "deps": [],
   "version": "0.2.0"