Bump the release version of the build images from 2024a to 2024b

From now on the images build on this branch are named with 2024b infix
in their tags.

Helps to move the [1] further.

* [1] https://issues.redhat.com/browse/RHOAIENG-12621

Author: jstourac

Makefile

@@ -1,5 +1,5 @@
 IMAGE_REGISTRY   ?= quay.io/opendatahub/workbench-images
-RELEASE	 		 ?= 2024a
+RELEASE	 		 ?= 2024b
 # additional user-specified caching parameters for $(CONTAINER_ENGINE) build
 CONTAINER_BUILD_CACHE_ARGS ?= --no-cache
 # whether to build all dependent images or just the one specified