Bump value from 2.8.8 to 2.8.9-ea-1

Bumps [value](https://github.com/immutables/immutables) from 2.8.8 to 2.8.9-ea-1.
- [Release notes](https://github.com/immutables/immutables/releases)
- [Changelog](https://github.com/immutables/immutables/blob/master/CHANGELOG.md)
- [Commits](https://github.com/immutables/immutables/commits)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

pom.xml

@@ -28,7 +28,7 @@
      -->
     <apache.log4j.version>2.13.3</apache.log4j.version>
     <assertj.version>3.19.0</assertj.version>
-    <immutables.version>2.8.8</immutables.version>
+    <immutables.version>2.8.9-ea-1</immutables.version>
     <jackson.version>2.10.1</jackson.version>
     <json.unit.version>2.19.0</json.unit.version>
     <junit.version>4.13.1</junit.version>