Fix reference of tags creating nested lists

The !reference keyword was creating a nested list inside the tags parameter. This MR reverts to explicitly listing all tags every time.

assigned to @ydayer

@samuel.gaist: This should fix the nightlies not running at all.

@andre.anjos: Note that tags in the ci.yaml config do not support !reference of lists (unlike scripts that accept nested list).

enabled an automatic merge when the pipeline for 5d12ac1d succeeds

merged

mentioned in commit 20800b22

Please cross-check that the same kind of error is not implemented on bob/dev-profile>

It is ok in that package: only scripts variables are using !reference.

Righty - thx for double-checking.