Push 'latest' tagged images

[1aziz]

Describe the solution you'd like
Currently, we're pushing images tagged with the PR number, SHA or the master branch name (based on the trigger types
and conditions defined in the prep step).
However, we don't have any additional conditions for triggers related to master / release tags, therefore the latest tag has been remained unchanged and containersol/externalsecret-operator:latest is no longer the same as containersol/externalsecret-operator:master or any other latest tagged-release.

What is the added value?
Offering a consistent 'latest' tag helps people to run the controller deployment using the default settings in our Makefile. Using a latest tag could be useful for demo and testing purposes.

Give us examples of the outcome
We will need to provide a new condition in the prep step adding a new value to the TAGS (outputted as tags in the pipeline).