Move OL fixpack to 20.0.0.3

[scottkurz]

Signed-off-by: Scott Kurz skurz@us.ibm.com

Checklist:

• [X] Read the Code of Conduct and Contributing Guidelines.

• [ X] Followed the commit message guidelines.

• [X ] Stack adheres to Appsody stack structure.

Modifying an existing stack:

• [X ] Updated the stack version in stack.yaml

Related Issues:

• Fixes #740
• Updates Open Liberty version to Fix Pack 20.0.0.3

[scottkurz]

@Kamran64 @EnriqueL8 - ready to merge. Thank you.