Accomodate bootstrap string

So, often, we need to bootstrap to a new release. Currently, the release cadence is based on what Debian's is, which is roughtly around every 2 years. But given the wider momentum Apertis has, this could improve.

Otherwise, too, it makes sense to add the 'bootstrap' keyword in the checklist. We don't want to remember 2 years down the line, again, on what all corners we need to add such settings to.

Tested locally:

In [2]: downstream="v2022dev2"

In [3]: foostream="bullseyebootstrap"

In [4]: re.search(r'(dev[0-9]|pre)$', downstream)
Out[4]: <re.Match object; span=(5, 9), match='dev2'>

In [5]: re.search(r'(dev[0-9]|pre)$', foostream)

In [6]: foostream="bootstrap"

In [7]: re.search(r'(dev[0-9]|pre)$', foostream)

In [8]: re.search(r'(dev[0-9]|pre|bootstrap)$', foostream)
Out[8]: <re.Match object; span=(0, 9), match='bootstrap'>

In [9]: foostream="bullseyebootstrap"

In [10]: re.search(r'(dev[0-9]|pre|bootstrap)$', foostream)
Out[10]: <re.Match object; span=(8, 17), match='bootstrap'>

Signed-off-by: Ritesh Raj Sarraf ritesh.sarraf@collabora.com