Use latest available Apache Struts2 GA 2.5.20 release

[jogep]

• Use latest Struts2 version 2.5.20 in dependencies
• Use latest support plugin 1.1.0 with additional useful interceptors and predefined stack in samples and archetypes

[sapessi]

Looks like you have some deps issues:

[INFO] --- maven-enforcer-plugin:1.0:enforce (enforce) @ aws-serverless-java-container-struts2 ---
[ERROR] 
Dependency convergence error for org.apache.logging.log4j:log4j-api:2.11.1 paths to dependency are:
+-com.amazonaws.serverless:aws-serverless-java-container-struts2:1.4-SNAPSHOT
  +-org.apache.struts:struts2-core:2.5.20
    +-org.apache.logging.log4j:log4j-api:2.11.1
and
+-com.amazonaws.serverless:aws-serverless-java-container-struts2:1.4-SNAPSHOT
  +-org.apache.logging.log4j:log4j-to-slf4j:2.10.0
    +-org.apache.logging.log4j:log4j-api:2.10.0
[ERROR] 
Dependency convergence error for commons-fileupload:commons-fileupload:1.3.3 paths to dependency are:
+-com.amazonaws.serverless:aws-serverless-java-container-struts2:1.4-SNAPSHOT
  +-com.amazonaws.serverless:aws-serverless-java-container-core:1.4-SNAPSHOT
    +-commons-fileupload:commons-fileupload:1.3.3
and
+-com.amazonaws.serverless:aws-serverless-java-container-struts2:1.4-SNAPSHOT
  +-org.apache.struts:struts2-core:2.5.20
    +-commons-fileupload:commons-fileupload:1.4

[jogep]

@sapessi I fixed the dependency conflict and it builds now. I upgraded the fileupload to 1.4 project wide. Hope this is fine for you.

[sapessi]

Merged changes in the core branch where I'm working on some other issues. This will go out as a patch release with the bug fixes.