When there are more than 15 reviewers, the `set_assignee` script was
adding the reviewers more or less on a random basis because the input
set was arbitrarily ordered (thanks to how Python "set" works), and the
attempt to add any reviewers beyond the count of 15 results in the
previoulsy added reviewer being removed.
This commit updates the `set_assignee` script such that:
1. The collaborator list (input for generating the reviewer list) is
ordered by the area match, such that the collaborators of the most
relevant area come first.
2. The reviewers of the relevant areas are added first, until the total
reviewer count is 15. The script does not attempt to add more than
15 reviewers because that can result in the previously added
reviewers being removed from the list.
Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
faf4208295