Changed find_packages() for find_namespace_packages() since

translation dir not included as package.

```bash
\############################
\# Package would be ignored #
\############################

Python recognizes 'scipplan.translation' as an importable package,
but it is not listed in the `packages` configuration of setuptools.

'scipplan.translation' has been automatically added to the distribution only
because it may contain data files, but this behavior is likely to change
in future versions of setuptools (and therefore is considered deprecated).

Please make sure that 'scipplan.translation' is included as a package by using
the `packages` configuration field or the proper discovery methods
(for example by using `find_namespace_packages(...)`/`find_namespace:`
instead of `find_packages(...)`/`find:`).

You can read more about "package discovery" and "data files" on setuptools
documentation page.
```

Author: Ariges770

setup.py

@@ -1,6 +1,6 @@
 import scipplan
 
-from setuptools import setup, find_packages
+from setuptools import setup, find_namespace_packages
 
 def readme():
     with open("README.md") as f:
@@ -15,7 +15,7 @@ def readme():
     license="MIT License",
     author=scipplan.__author__,
     author_email=scipplan.__email__,
-    packages=find_packages(),  # Automatically find all packages
+    packages=find_namespace_packages(),  # Automatically find all packages
     include_package_data=True,
     package_data={
         # "": ["translation/*.txt"],