Add `overrideHttpPut` Option

[bendvc]

Description

This change added a new option to the api. overrideHttpPut which is defaulted tofalse that will ensure all commands that using http PUT as specified in their swagger doc will masquerade as http POST. Their http method will then be overridden with an additional header x-dw-http-method-override: 'PUT' to ensure things work server side.

This was done on the API side for security reasons, so it is out of our hands. More information about this can be found here --> https://documentation.demandware.com/DOC1/index.jsp?topic=%2Fcom.demandware.dochelp%2FOCAPI%2F18.8%2Fusage%2FHttpMethods.html

Type of change

• [x] 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 not work as expected)
• [ ] Documentation update

Changes

• Add new logic to callAPI method to use POST when allowHttpPut is false and the method type is put.
• Updated change log
• Added option and function docs

How to test this PR?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

Checklist:

• [ ] My code follows the style guidelines of this project (npm run lint)
• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation (README.md and CHANGELOG.md)
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes (npm test)

[olibrook]

Looks really great! Only thing is, I kinda hate the name allowHttpPut, because we're always going to have methods called putCart or whatever, and they are always going to be "allowed". Could we rename the flag to overrideHttpPut? Users can then probably imagine that would correspond to a commonly-used "x-method-override" header, too.

[kevinxh]

Looking pretty good.

One thing we might want to do is add some documentation around this flag, maybe here: https://github.com/mobify/commercecloud-ocapi-client#-configuration

(I agree with Oli, word 'override' sounds more intuitive in this case)

[bendvc]

I've addressed both of your comments. This involved inverting the logic a little as the name change is the inverse. Please take a look