Basic authentication headers not added to code samples

[badsyntax]

Describe the bug

When using a basicAuth security schema, the Authorization header is not added to the code samples.

• - I have checked that my input document is valid OpenAPI 2.0/3.0.x or AsyncAPI 1.x

To Reproduce
Steps to reproduce the behavior:

1. Command-line: widdershins --language_tabs 'shell:curl' --summary ./bug.yml -o source/index.html.md
2. My input file: https://gist.github.com/badsyntax/c2eb92b3660bdce3da6186615e20939b
3. Scroll down to curl -X POST /example
4. See that the basic auth headers are not added

Expected behavior
I expect to see Authorization: Basic abcd123 similar to bearerAuth

I will send a PR.