adding screenshot and updating readme to point to it

experiment/production/housing/v-acorn-squash/README.md

@@ -3,7 +3,7 @@ Popufare Driver Interface Unit Housing, Version: `Acorn Squash`
 
 ###### 2020-01-20
 
-![housing preview](img/housing.png)
+![housing preview](img/diu-acorn-squash-housing-preview.png)
 
 This is version 'acorn squash' of the Driver Interface Unit (DIU) housing.
 There is a legacy mounting plate that needs to be attached to.