HADOOP-17940. Upgrade Kafka to 2.8.1 (#3488)

Reviewed-by: Masatake Iwasaki <iwasakims@apache.org>
(cherry picked from commit 2068b0041c05a7b53f32606cc24922cfac299ca8)

hadoop-project/pom.xml

@@ -48,7 +48,7 @@
     <!-- Version number for xerces used by JDiff -->
     <xerces.jdiff.version>2.11.0</xerces.jdiff.version>
 
-    <kafka.version>2.4.0</kafka.version>
+    <kafka.version>2.8.1</kafka.version>
 
     <hadoop.assemblies.version>3.2.3</hadoop.assemblies.version>
     <commons-daemon.version>1.0.13</commons-daemon.version>