Provide access to JAXB when using Java 9
Provide access to JAXB when using Java 9

Java 9 doesn't consider JAXB part of Java EE APIs as explained here (https://stackoverflow.com/a/43574427/38483). 

Without that extra parameter we get this exception when running the docker image:

```
Caused by: java.lang.ClassNotFoundException: javax.xml.bind.DatatypeConverter
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:582)
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:185)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:496)
        ... 70 more
```
findify/s3mock