Upgrade log4j to version 2.17.1

Author: vvanholl

build.gradle

@@ -53,7 +53,7 @@ ext {
     versions = [
         "elasticsearch": es_version,
         "prometheus"   : "0.8.0",
-        "log4j"        : "2.17.0",
+        "log4j"        : "2.17.1",
         "junit"        : "4.12"
     ]
 }