Remove lambda code smells from policyagent/clients

Change-Id: I9f4ef0041989d6565b0982e35e3521968e7d59fc
Issue-ID: NONRTRIC-142
Signed-off-by: elinuxhenrik <henrik.b.andersson@est.tech>
diff --git a/policy-agent/pom.xml b/policy-agent/pom.xml
index 78ff193..b8dcbc4 100644
--- a/policy-agent/pom.xml
+++ b/policy-agent/pom.xml
@@ -48,7 +48,7 @@
     <properties>
         <java.version>11</java.version>
         <springfox.version>2.9.2</springfox.version>
-        <immutable.version>2.7.1</immutable.version>
+        <immutable.version>2.7.4</immutable.version>
         <sdk.version>1.1.6</sdk.version>
         <swagger.version>2.0.0</swagger.version>
         <json.version>20180130</json.version>