chore: dump maven version along with java (#677)

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Source-Link: googleapis/synthtool@8eae023

.kokoro/build.sh

@@ -23,8 +23,8 @@ cd ${scriptDir}/..
 # include common functions
 source ${scriptDir}/common.sh
 
-# Print out Java version
-java -version
+# Print out Maven & Java version
+mvn -version
 echo ${JOB_TYPE}
 
 # attempt to install 3 times with exponential backoff (starting with 10 seconds)

synth.metadata

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/google-auth-library-java.git",
-        "sha": "469b160d1c047f7c0284ccc1da576d116f140e3d"
+        "sha": "318281bba4aef9edd7500ea01a789a1581618cb8"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "7332178a11ddddc91188dc0f25bca1ccadcaa6c6"
+        "sha": "8eae0234a16b26c2ff616d305dbd9786c8b10a47"
       }
     }
   ],