requests dependency confusion

Hi, maintainers:

i'm attempting to use this awesome package in my project to do some workflow integration.
when i try to `pip install -r requirements.txt`, it says

```
The conflict is caused by:
The user requested requests==2.27.1
camunda-external-task-client-python3 4.3.0 depends on requests==2.24.0

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict
```

here is the part of my `requirements.txt`:
```
camunda-external-task-client-python3==4.3.0
requests==2.27.1
```

but i have another package which uses requests package version >= 2.24.0
when i remove `==4.3.0`, it works, got an old version 3.0.0,

maybe here are some clue to find out the reason:
the 2.24.0 appears in `setup.cfg`, but in `requirements.txt` it is 2.26.0

https://github.com/camunda-community-hub/camunda-external-task-client-python3/blob/ed7a493942dea6c1b570298f67b09dc12ff7da11/setup.cfg#L26

https://github.com/camunda-community-hub/camunda-external-task-client-python3/blob/ed7a493942dea6c1b570298f67b09dc12ff7da11/requirements.txt#L1

i'm new to python, i don't know how pypi/pip works.
but i guess it was just a mistyping of manifest .

thx.