Fix priority thresholds

[chevdor]

This PR fix the threshold for Medium prio.

[dvdplm]

Would be good to have a test for these perhaps?

[chevdor]

@dvdplm how do you imagine such as test ?

[dvdplm]

@dvdplm how do you imagine such as test ?

Yeah good question. Would it be possible to use past releases (whose PRs likely don't change labels) and assert that the priorities assigned are what we expect?

[chevdor]

I would not assume that the past was correct :)
What could be done is to create one or more synthetic context.json(this is where the data about the priorities and labels is located) then generated the release notes and compare with our expectations.

The templates are rather split so we could check each part individually.