feat: add region eu-west-3

[magrinj]

Description of changes

Add eu-west-3 region.
Not sure of the changes, but it seems to work locally.

Issue #5832

Description of how you validated changes

Run cli binary locally to confirm it works.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

Merging #8056 (d1029ea) into master (7b5de7b) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #8056   +/-   ##
=======================================
  Coverage   54.14%   54.14%           
=======================================
  Files         657      657           
  Lines       37484    37484           
  Branches     7696     7696           
=======================================
  Hits        20295    20295           
  Misses      16349    16349           
  Partials      840      840           

Impacted Files	Coverage Δ
...lify-provider-awscloudformation/src/aws-regions.js	100.00% <ø> (ø)

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[cjihrig]

Thanks for the PR. In general, we can't accept external contributions to enable new regions. However, eu-west-3 support landed recently in #8094, and should be available in the next release.