Add 'Content-Length: 0' header on multipart upload creation

[waahm7]

Description of changes:
Duplicate to #426 to fix the CI.

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

Attention: Patch coverage is 66.66667% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 89.50%. Comparing base (03341c5) to head (2c53dd5).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #428      +/-   ##
==========================================
- Coverage   89.52%   89.50%   -0.02%     
==========================================
  Files          20       20              
  Lines        6012     6015       +3     
==========================================
+ Hits         5382     5384       +2     
- Misses        630      631       +1     

Files	Coverage Δ
source/s3_request_messages.c	73.92% <66.66%> (-0.06%)	⬇️