Bump hadoop-common in /tensorflow/java/maven/tensorflow-hadoop

Bumps hadoop-common from 2.6.0 to 3.2.4.

---
updated-dependencies:
- dependency-name: org.apache.hadoop:hadoop-common
  dependency-type: direct:production
...

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Author: dependabot[bot]

tensorflow/java/maven/tensorflow-hadoop/pom.xml

@@ -14,7 +14,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>1.6</maven.compiler.source>
         <maven.compiler.target>1.6</maven.compiler.target>
-        <hadoop.version>2.6.0</hadoop.version>
+        <hadoop.version>3.2.4</hadoop.version>
         <protobuf.version>3.5.1</protobuf.version>
         <junit.version>4.13.1</junit.version>
     </properties>