Add version to font-face src url

Closes #5034

- Added `?v=0.1' to the font file URL to force a refresh of any old files with the same name

core/client/app/styles/modules/icons.scss

@@ -26,7 +26,7 @@
 
 @font-face {
     font-family: 'GhostIcons';
-    src:url('fonts/icons.woff') format('woff');
+    src:url('fonts/icons.woff?v=0.1') format('woff'); // Increment the ?v number every time the font files are regenerated
     font-weight: normal;
     font-style: normal;
 }