Fixes issue where label will not display when value is False

If text value evaluates to False, label will not display.
This change resolves that issue.

Tested with proximity data that returns 0 when no object is present.

Author: kattni

adafruit_display_text/label.py

@@ -79,7 +79,7 @@ def __init__(self, font, *, text=None, max_glyphs=None, color=0xffffff,
         self._line_spacing = line_spacing
         self._boundingbox = None
 
-        if text:
+        if text is not None:
             self._update_text(str(text))