Allow to build on s390_64

Motivation:

It is not possible to build Netty on an s390_64 platform.

Modifications:

Modify pom.xml so that s390_64 is acceptable as os.detected.arch.

Result:

Netty can be built on an s390_64 platform.

Signed-off-by: Tatsushi Inagaki <e29253@jp.ibm.com>

pom.xml

@@ -768,10 +768,10 @@
                 </requireMavenVersion>
                 <requireProperty>
                   <regexMessage>
-                    x86_64/AARCH64/PPCLE64 JDK must be used.
+		     x86_64/AARCH64/PPCLE64/s390x_64 JDK must be used.
                   </regexMessage>
                   <property>os.detected.arch</property>
-                  <regex>^(x86_64|aarch_64|ppcle_64)$</regex>
+                  <regex>^(x86_64|aarch_64|ppcle_64|s390_64)$</regex>
                 </requireProperty>
               </rules>
             </configuration>