Update ProB 2 version to 3.12.0

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## [(next version)](https://gitlab.cs.uni-duesseldorf.de/api/v4/projects/848/jobs/artifacts/master/raw/build/libs/prob2-jupyter-kernel-1.2.1-SNAPSHOT-all.jar?job=test)
 
-* Updated ProB 2 to version 4.0.0-SNAPSHOT.
+* Updated ProB 2 to version 3.12.0.
 * Added a `:language` command to allow changing the language used to parse user input. For example `:language event_b` can be used to switch to Event-B syntax when a non-Event-B machine is loaded (or no machine at all).
 * Improved the performance of loading machines by reusing the existing instance of ProB instead of starting a new one for each machine.
 * Improved error highlighting for machines loaded from files and not from the notebook.

build.gradle

@@ -40,7 +40,7 @@ dependencies {
 	implementation(group: "ch.qos.logback", name: "logback-classic", version: "1.2.3")
 	implementation(group: "com.google.code.gson", name: "gson", version: "2.8.6")
 	implementation(group: "com.google.guava", name: "guava", version: "28.2-jre")
-	implementation(group: "de.hhu.stups", name: "de.prob2.kernel", version: "4.0.0-SNAPSHOT")
+	implementation(group: "de.hhu.stups", name: "de.prob2.kernel", version: "3.12.0")
 	implementation(group: "io.github.spencerpark", name: "jupyter-jvm-basekernel", version: "2.3.0")
 	implementation(group: "org.jetbrains", name: "annotations", version: "18.0.0")
 	implementation(group: "se.sawano.java", name: "alphanumeric-comparator", version: "1.4.1")