Upgrade DB2 operator/version

[andrercm]

Currently we're using db2_version: 11.5.7.0-cn4 along with our automation by default. Accordingly to DB2 documentation, this is compatible with OCP 4.0 (yeah!): https://www.ibm.com/docs/en/db2/11.5?topic=1157-upgrading-updating

We need to bump it to s11.5.8.0-cn1 which is the latest available version, compatible with OCP 4.10/4.12. https://www.ibm.com/docs/en/db2-warehouse?topic=db2-warehouse-rhos-k8s

Also we need to make sure that MAS apps using DB2 are compatible with the new version, so mainly two tests needs to be done:

• [ ] clean install MAS apps in db2_version: s11.5.8.0-cn1, so need to set it as default in db2 role.
• [ ] make sure the db2 role also allows upgrading db2_version: 11.5.7.0-cn4 to db2_version: s11.5.8.0-cn1, so need to have MAS apps installed in db2_version: 11.5.7.0-cn4 then running the db2 to switch db2ucluster to db2_version: s11.5.8.0-cn1 allows the db2 upgrade and no affect to MAS apps.

[whitfiea]

We should move to 11.5.8.0-cn2 which would be available also when 110508.0.2 is available.

[whitfiea]

Upgrading from 11.5.7.0-cn4 to s11.5.8.0 works fine using the 110508.0.0 db2u operator

[durera]

Looks like this has already been done: ibm/mas_devops/roles/db2/defaults/main.yml

db2_version: "{{ lookup('env', 'DB2_VERSION') | default('s11.5.8.0', true) }}"