[CODEC-257] Update from Java 7 to Java 8.

Author: Gary Gregory

.travis.yml

@@ -17,7 +17,6 @@ language: java
 sudo: false
 
 jdk:
-  - openjdk7
   - oraclejdk8
   - oraclejdk9
   - oraclejdk11

pom.xml

@@ -224,8 +224,8 @@ limitations under the License.
     </dependency>
   </dependencies>
   <properties>
-    <maven.compiler.source>1.7</maven.compiler.source>
-    <maven.compiler.target>1.7</maven.compiler.target>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
     <commons.componentid>codec</commons.componentid>
     <commons.module.name>org.apache.commons.codec</commons.module.name>
     <commons.jira.id>CODEC</commons.jira.id>