Keep copyright up to date in documentation

Author: Alec Delaney

docs/conf.py

@@ -21,6 +21,7 @@
 #
 import os
 import sys
+import datetime
 
 sys.path.insert(0, os.path.abspath(".."))
 
@@ -62,6 +63,7 @@
 
 # General information about the project.
 project = "Adafruit AMG88xx Library"
+current_year = str(datetime.datetime.now().year)
 copyright = "2017, Dean Miller for Adafruit Industries"
 author = "Dean Miller"