Try using alias for docker image version

The docs show that the 20.20.1 tag has an alias of 20.20. Not sure
why it wasn't able to pull the image using 20.20.1, but going to
try the alias instead.

https://circleci.com/developer/images/image/cimg/node

Author: mattherman

.circleci/config.yml

@@ -3,7 +3,7 @@ version: 2.1
 executors:
   node-maintenance:
     docker:
-      - image: cimg/node:20.20.1
+      - image: cimg/node:20.20
     environment:
       - MB_SLOW_TEST_TIMEOUT: 10000
   node-active: