[UPMERGE] 2.0 -> 2.1 (#410)

This PR has been generated automatically.
For more details see
[upmerge_pr.yaml](/Sylius/InvoicingPlugin/blob/1.0/.github/workflows/upmerge_pr.yaml).

**Remember!** The upmerge should always be merged with using `Merge pull
request` button.

In case of conflicts, please resolve them manually with usign the
following commands:
```
git fetch upstream
gh pr checkout <this-pr-number>
git merge upstream/2.1 -m "Resolve conflicts between 2.0 and 2.1"
```

If you use other name for the upstream remote, please replace `upstream`
with the name of your remote pointing to the `Sylius/InvoicingPlugin`
repository.

Once the conflicts are resolved, please run `git merge --continue` and
push the changes to this PR.

Author: Rafikooo

phpstan.neon

@@ -9,10 +9,6 @@ parameters:
         # Makes PHPStan crash
         - 'src/DependencyInjection/Configuration.php'
 
-        # Test dependencies
-        - 'tests/Application/app/**.php'
-        - 'tests/Application/src/**.php'
-
     ignoreErrors:
         - identifier: missingType.generics
         - identifier: missingType.iterableValue