switch to modularized javadoc format

Signed-off-by: Lukas Jungmann <lukas.jungmann@oracle.com>

.travis.yml

@@ -13,8 +13,7 @@ dist: bionic
 
 jdk:
   - oraclejdk11
-# jdk 14 does not provide JDK 8 compatible javadoc, disabled for now
-#  - oraclejdk14
+  - oraclejdk14
 
 cache:
   directories:

jaxb-api/pom.xml

@@ -78,14 +78,7 @@
                 <plugin>
                     <artifactId>maven-javadoc-plugin</artifactId>
                     <configuration>
-                        <source>1.8</source>
-                        <release>8</release>
-                        <additionalOptions>
-                            <additionalOption>--frames</additionalOption>
-                        </additionalOptions>
-                        <sourceFileExcludes>
-                            <sourceFileExclude>module-info.java</sourceFileExclude>
-                        </sourceFileExcludes>
+                        <release>11</release>
                         <nodeprecated>false</nodeprecated>
                         <notimestamp>true</notimestamp>
                         <use>false</use>