Fix #328 update travis to openjdk11 (#329)

.travis.yml

@@ -3,7 +3,7 @@ language: java
 os:
   - linux
 jdk:
-  - openjdk8
+  - openjdk11
 cache:
   directories:
     - "$HOME/.m2/repository"

README.md

@@ -96,4 +96,4 @@ See the License for the specific language governing permissions and
 limitations under the License.
 
 
-[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgit.luolix.top%2Fproshin-roman%2Ffinapi-java-client.svg?type=large)](https://app.fossa.io/projects/git%2Bgit.luolix.top%2Fproshin-roman%2Ffinapi-java-client?ref=badge_large)
+[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgit.luolix.top%2Fproshin-roman%2Ffinapi-java-client.svg?type=large)](https://app.fossa.io/projects/git%2Bgit.luolix.top%2Fproshin-roman%2Ffinapi-java-client?ref=badge_large)

pom.xml

@@ -21,6 +21,7 @@
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>8</maven.compiler.source>
   </properties>
 
   <groupId>org.proshin</groupId>
@@ -144,8 +145,8 @@
         <artifactId>maven-compiler-plugin</artifactId>
         <version>3.8.1</version>
         <configuration>
-          <source>1.8</source>
-          <target>1.8</target>
+          <source>${maven.compiler.source}</source>
+          <target>${maven.compiler.source}</target>
           <encoding>UTF-8</encoding>
         </configuration>
       </plugin>
@@ -295,6 +296,7 @@
             <configuration>
               <encoding>UTF-8</encoding>
               <additionalJOption>-Xdoclint:none</additionalJOption>
+              <source>${maven.compiler.source}</source>
             </configuration>
             <executions>
               <execution>