rstcheck does not have a -c option

[daltonv]

Describe the bug
The megalinter config (as of megalinter v7.2.1) RST_RSTCHECK_CONFIG_FILE uses the wrong cli arg for passing a config file to rstcheck

To Reproduce
Steps to reproduce the behavior:

1. Modify the .mega-linter.yml file to set RST_RSTCHECK_CONFIG_FILE like

   RST_RSTCHECK_CONFIG_FILE: pyproject.toml

2. Run megalinter and see it fail with:

- Using [rstcheck v6.1.2] https://megalinter.io/7.2.1/descriptors/rst_rstcheck
- MegaLinter key: [RST_RSTCHECK]
- Rules config: [/github/workspace/pyproject.toml]
- Number of files analyzed: [4]
[rstcheck] docs/cpu.rst - ERROR - 1 error(s)
--Error detail:
Usage: rstcheck [OPTIONS] FILES...
Try 'rstcheck --help' for help.
╭─ Error ──────────────────────────────────────────────────────────────────────╮
│ No such option: -c  

Expected behavior
Instead this config option should use the correct --config argument.

Additional context
Additionally I think rstcheck should be installed with pip install rstcheck[toml,sphinx] to support sphinx directives in rst files and toml config files.

[nvuillam]

@daltonv thanks for catching the issue, PR is on the way :)