Prepare next development iteration (#1206)

Co-authored-by: jonas-wielage-sonarsource <jonas-wielage-sonarsource>
GitOrigin-RevId: 7dc7ce6890ad9de0314d2239e21541b8b8823fe4

Author: github-actions[bot]

gradle.properties

@@ -1,5 +1,5 @@
 group=org.sonarsource.text
-version=2.38-SNAPSHOT
+version=2.39-SNAPSHOT
 description=Analyzer for Text Files
 projectTitle=SonarSource Text Analyzer