Add ap-northeast-1 (Tokio) region support

[juliodelgadoaws]

Issue #, if available:

Description of changes:

Add ap-northeast-1 (Tokio) region support

Merge Checklist

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• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have updated the changelog with a description of my changes (if appropriate)
• I have updated any necessary documentation (if appropriate)

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

[codecov-io]

Codecov Report

Merging #196 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #196   +/-   ##
=======================================
  Coverage   91.03%   91.03%           
=======================================
  Files          42       42           
  Lines        2699     2699           
=======================================
  Hits         2457     2457           
  Misses        242      242

Impacted Files	Coverage Δ
src/sagemaker/amazon/amazon_estimator.py	83.63% <ø> (ø)	⬆️

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