Sync parallel.md

parallel.md

@@ -2,7 +2,7 @@
 notice: 'This file is imported and can be edited at https://github.com/amphp/parallel/blob/2.x/README.md'
 title: 'Parallel Processing in PHP'
 description: 'Learn how to do true parallel processing in PHP using multiple processes or native threads, without blocking and no extensions required.'
-image: undraw/undraw_logistics.svg
+image: undraw/undraw_upgrade.svg
 permalink: /parallel
 source: 'https://github.com/amphp/parallel/blob/2.x/README.md'
 layout: docs