Add example for request chaining in body payload

[sapiderman]

Monika Pull Request (PR)

What feature/issue does this PR add

1. Implements Docs: Response data in the next request body #757
2. Missing example for request chaining in body

How did you implement / how did you fix it

1. Adding specific example where previous request is used in body
2. Test the example

How to test

1. Use the following monika.yaml

probes:
  - id: probe-01
    name: 'body from resonse'
    interval: 10

    requests:
      - url: https://reqres.in/api/users/1
        method: GET
        timeout: 5000
        saveBody: false
        headers:
          Content-Type: application/json; charset=utf-8
      - url: https://reqres.in/api/login
        method: POST
        timeout: 1000
        headers:
          Content-Type: application/json; charset=utf-8
        body:
          email: '{{ responses.[0].body.data.email }}'
          password: password

2. Then run monika -c monica.yaml -s 0

[codecov]

Codecov Report

Merging #780 (0814976) into main (2b36ad0) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #780   +/-   ##
=======================================
  Coverage   48.60%   48.60%           
=======================================
  Files          69       69           
  Lines        2337     2337           
  Branches      459      459           
=======================================
  Hits         1136     1136           
  Misses       1030     1030           
  Partials      171      171