Excavator: Downgrade Immutables to the latest stable release (#768)

Author: svc-excavator-bot

versions.lock

@@ -39,7 +39,7 @@ org.assertj:assertj-core:3.22.0 (3 constraints: bf2bc004)
 org.checkerframework:checker-qual:3.12.0 (4 constraints: 773a1325)
 org.checkerframework:dataflow-errorprone:3.15.0 (3 constraints: 6736f3f2)
 org.eclipse.jgit:org.eclipse.jgit:5.13.0.202109080827-r (2 constraints: b1299390)
-org.immutables:value:2.9.0 (3 constraints: f4246e03)
+org.immutables:value:2.8.8 (3 constraints: fb24f005)
 org.mockito:mockito-core:4.3.1 (3 constraints: b724cede)
 org.mockito:mockito-errorprone:4.1.0 (1 constraints: fb1102f9)
 org.objenesis:objenesis:3.2 (2 constraints: 4d1c5eb4)

versions.props

@@ -4,6 +4,6 @@ com.palantir.safe-logging:* = 1.21.0
 com.palantir.tokens:auth-tokens = 3.11.0
 org.apache.commons:commons-lang3 = 3.12.0
 org.assertj:assertj-core = 3.22.0
-org.immutables:* = 2.9.0
+org.immutables:* = 2.8.8
 org.junit.jupiter:* = 5.8.2
 org.mockito:mockito-core = 4.3.1