Bumped sonar version

Author: Timothy G. Rundle

pom.xml

@@ -96,7 +96,7 @@
         <logback.version>1.0.13</logback.version>
         <mockito.version>1.9.0</mockito.version>
         <slf4j.version>1.7.21</slf4j.version>
-        <sonar.version>6.7</sonar.version>
+        <sonar.version>7.3</sonar.version>
         <sonar-orchestrator.version>3.22.0.1791</sonar-orchestrator.version>
         <sonarlint.version>4.0.0.2052</sonarlint.version>
         <sslr.version>1.23</sslr.version>