Update README_Cognito_UserPools_PreSignup.md

[AaronMulgrew]

Issue #, if available:

Description of changes:
Simply make the presignup function linter approved.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[bmoffatt]

AWS CodeBuild CI Report

• CodeBuild project: aws-lambda-go-github-ci
• Commit ID: faf19d0
• Result: SUCCEEDED
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[codecov-io]

Codecov Report

Merging #258 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #258   +/-   ##
=======================================
  Coverage   74.59%   74.59%           
=======================================
  Files          20       20           
  Lines         681      681           
=======================================
  Hits          508      508           
  Misses        128      128           
  Partials       45       45

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[bmoffatt]

AWS CodeBuild CI Report

• CodeBuild project: aws-lambda-go-github-ci
• Commit ID: be98117
• Result: SUCCEEDED
• Build Logs (available for 30 days)

Powered by github-codebuild-logs, available on the AWS Serverless Application Repository