python setuptools setup.cfg: Including main- and subpackages in the build dir

I would like to create a pip package for my python software using a setup.cfg file. My program is currently structured as following:

mypkg
├── setup.cfg
└── src
    ├── subpkg
    │   └── __init__.py
    ├── __init__.py
    └── file_1.py
    ...

so far, using the setuptools find_packages() function allowed me to add my main package as well as the subpackage to my build package. When using a setup.cfg file however, I am not able to include both in my package anymore. The documentation shows that subpackages can be included by adding the option

[options]
packages = find:
package_dir =
    =src

[options.packages.find]
where = src
include = *

But this only includes the subpackage files and not the main package files in my case. Is there a way for me to include all my files while still making use of a setup.cfg setup file?

from python setuptools setup.cfg: Including main- and subpackages in the build dir