Update jpa-cdi-testing to run on JDK 14

[Bukama]

@gunnarmorling asked if I could have a look at the jpa-cdi-testing project and open an PR to make it run on JDK 14. Here it is.

C:\JDK\Java14\bin\java.exe -Dmaven.multiModuleProjectDirectory=C:\Git\hibernate-demos\other\cdi-jpa-testing -  [...]
[INFO] Scanning for projects...
[INFO] 
[INFO] ----------------< org.hibernate.demos:jpa-cdi-testing >-----------------
[INFO] Building Demo for testing CDI + JPA + JTA under Java SE 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 

[...]


[INFO] --- maven-jar-plugin:3.0.2:jar (default-jar) @ jpa-cdi-testing ---
[INFO] Building jar: C:\Git\hibernate-demos\other\cdi-jpa-testing\target\jpa-cdi-testing-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  17.627 s

fixes #43