Fix for KeyError: 31

Added a second check for checking if key exists in the dictionary.

inkycal/modules/inkycal_calendar.py

@@ -258,6 +258,7 @@ class Calendar(inkycal_module):
 
       # Draw a border with specified parameters around days with events
       for days in days_with_events:
+        if days in grid:
           draw_border(
             im_colour,
             grid[days],