chore: add a dependabot workflow, update to latest Intellij Gradle plugin

Signed-off-by: Stephane Bouchet <[email protected]>

Author: sbouchet

gradle.properties

@@ -5,7 +5,7 @@ nexusUser=invalid
 nexusPassword=invalid
 
 # Supported build number ranges and IntelliJ Platform versions -> https://plugins.jetbrains.com/docs/intellij/build-number-ranges.html
-sinceIdeaBuild=23.1
+sinceIdeaBuild=231
 
 # IntelliJ Platform Properties -> https://plugins.jetbrains.com/docs/intellij/tools-gradle-intellij-plugin.html#configuration-intellij-extension
 ideaVersion=2024.3