Have animal-sniffer check 1.6 compat as 1.8 will emit JDK6 bytecode

Author: Stephane Landelle

pom.xml

@@ -156,13 +156,13 @@
                 <configuration>
                     <signature>
                         <groupId>org.codehaus.mojo.signature</groupId>
-                        <artifactId>java15</artifactId>
+                        <artifactId>java16</artifactId>
                         <version>1.0</version>
                     </signature>
                 </configuration>
                 <executions>
                     <execution>
-                        <id>check-java-1.5-compat</id>
+                        <id>check-java-1.6-compat</id>
                         <phase>process-classes</phase>
                         <goals>
                             <goal>check</goal>