Update POM with correct Java versions

The Jena library requires Java 11.  This updates the POM file
to target Java 11.

Related to spdx/spdx-maven-plugin#76

Signed-off-by: Gary O'Neall <gary@sourceauditor.com>

Author: goneall

pom.xml

@@ -50,7 +50,7 @@
 		<profile>
 			<id>doclint-java8-disable</id>
 			<activation>
-				<jdk>[1.8,)</jdk>
+				<jdk>[1.8,11)</jdk>
 			</activation>
 			<properties>
 				<javadoc.opts>-Xdoclint:none</javadoc.opts>
@@ -161,8 +161,8 @@
 				<artifactId>maven-compiler-plugin</artifactId>
 				<version>3.6.1</version>
 				<configuration>
-					<source>1.8</source>
-					<target>1.8</target>
+					<source>11</source>
+					<target>11</target>
 					<encoding>${project.build.sourceEncoding}</encoding>
 					<showDeprecation>true</showDeprecation>
 					<showWarnings>true</showWarnings>