fix: fix body of patch operation in put cart entry

[fgmadeira]

Description

Add only quantity to the body of the PATCH operation.

Motivation and Context

Hybris was replying in error on put entry operation since we were sending the full entry on the patch.
This should fix the call to the cart/entries PATCH endpoint.

Types of changes

What types of changes does your code introduce? Put an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation improvement/changes

Checklist:

Go over all the following points, and put an x in all the boxes that apply.
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• My code passes the code style as defined by TSLint.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes and the overall coverage did not decrease.
• I ran all tests locally and they pass.
• All unit tests pass on CircleCi.

[fgmadeira]

Still unclear to me if .tsbuildinfo files are to be commited or not, so i maintained them