Add this-week-in-rust repo under automation

[Kobzol]

Repo: https://github.com/rust-lang/this-week-in-rust

CC @nellshamrell

Extracted from GH:

org = "rust-lang"
name = "this-week-in-rust"
description = "Data for this-week-in-rust.org"
bots = []

[access.teams]
twir-reviewers = "maintain"
security = "pull"

[access.individuals]
mariannegoldin = "maintain"
ericseppanen = "maintain"
rust-lang-owner = "admin"
rylev = "admin"
U007D = "maintain"
pietroalbini = "admin"
nellshamrell = "maintain"
extrawurst = "maintain"
Mark-Simulacrum = "admin"
bennyvasquez = "maintain"
cdmistman = "maintain"
badboy = "admin"
jdno = "admin"
andrewpollack = "maintain"

[[branch-protections]]
pattern = "master"
ci-checks = []
dismiss-stale-review = false
pr-required = false
review-required = false

[Kobzol]

Looks like twir isn't an actual GitHub team, hmm. So either we should keep only twir-reviewers, or make twir a GH team.

[ehuss]

Seems reasonable to me to just add a GitHub team whenever needed for these repo PRs.

[Kobzol]

Ok, created #1226.