[FIX] 02-numpy: update zero index image (#827)

* update zero index image to be in line with text

* use open font and bold text

* transpose column/row display

* python-zero-index.svg: update to sync with the lesson

* 02-numpy.md: switch to using python-zero-index.svg

Co-authored-by: Maxim Belkin <[email protected]>

Author: jdkent

_episodes/02-numpy.md

@@ -242,7 +242,7 @@ It takes a bit of getting used to,
 but one way to remember the rule is that
 the index is how many steps we have to take from the start to get the item we want.
 
-![Zero Index](../fig/python-zero-index.png)
+![Zero Index](../fig/python-zero-index.svg)
 
 > ## In the Corner
 >