upgraded requirements.txt versions

[rahulkumaran]

Fixes #623

Checklist

• I have read the [Contribution Guide] and my PR follows them.
• I updated my branch with the master branch.
• I have added necessary documentation about the functionality in the appropriate .md file

Short description of what this PR does:

• This PR upgrades the versions in requirements.txt
• The latest stable versions now exists there.

If you have questions, please send an email to SendGrid, or file a GitHub Issue in this repository.

[SendGridDX]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #624 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #624   +/-   ##
=======================================
  Coverage   84.77%   84.77%           
=======================================
  Files          35       35           
  Lines        1156     1156           
  Branches      172      172           
=======================================
  Hits          980      980           
  Misses         90       90           
  Partials       86       86

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[rahulkumaran]

@thinkingserious could you please review this? Thanks! 😄

[thinkingserious]

Hello @rahulkumaran,

Thanks again for the PR!

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[thinkingserious]

@rahulkumaran,

Could you please merge this into this branch instead? Thanks!

The python-http-client upgrade is a breaking change.

With Best Regards,

Elmer

[rahulkumaran]

@thinkingserious , sure! Will do that! There are a lot of conflicts arising currently when i try merging it into branch v4, so I'll send another PR for the same. Thanks!