Update version number in oomph setup file

Change version from 2.2.x to 2.3.x.

eclipse/spring-boot-project.setup

@@ -11,8 +11,8 @@
     xmlns:setup.workingsets="http://www.eclipse.org/oomph/setup/workingsets/1.0"
     xmlns:workingsets="http://www.eclipse.org/oomph/workingsets/1.0"
     xsi:schemaLocation="http://www.eclipse.org/oomph/setup/jdt/1.0 https://git.eclipse.org/c/oomph/org.eclipse.oomph.git/plain/setups/models/JDT.ecore http://www.eclipse.org/oomph/setup/maven/1.0 https://git.eclipse.org/c/oomph/org.eclipse.oomph.git/plain/setups/models/Maven.ecore http://www.eclipse.org/oomph/predicates/1.0 https://git.eclipse.org/c/oomph/org.eclipse.oomph.git/plain/setups/models/Predicates.ecore http://www.eclipse.org/oomph/setup/workingsets/1.0 https://git.eclipse.org/c/oomph/org.eclipse.oomph.git/plain/setups/models/SetupWorkingSets.ecore http://www.eclipse.org/oomph/workingsets/1.0 https://git.eclipse.org/c/oomph/org.eclipse.oomph.git/plain/setups/models/WorkingSets.ecore"
-    name="spring.boot.2.2.x"
-    label="Spring Boot 2.2.x">
+    name="spring.boot.2.3.x"
+    label="Spring Boot 2.3.x">
   <setupTask
       xsi:type="setup:VariableTask"
       type="FOLDER"