remove unused compatibility code

This change removes `__future__` imports and 'coding: utf-8' 
declarations.

Co-authored-by: Jason Racine <jason.racine@uplight.com>

poetry/factory.py

-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 from pathlib import Path
 from typing import TYPE_CHECKING
 from typing import Dict
@@ -10,17 +7,16 @@ from typing import Optional
 from cleo.io.io import IO
 from cleo.io.null_io import NullIO
 
+from poetry.config.config import Config
+from poetry.config.file_config_source import FileConfigSource
 from poetry.core.factory import Factory as BaseFactory
 from poetry.core.toml.file import TOMLFile
-
-from .config.config import Config
-from .config.file_config_source import FileConfigSource
-from .locations import CONFIG_DIR
-from .packages.locker import Locker
-from .packages.project_package import ProjectPackage
-from .plugins.plugin_manager import PluginManager
-from .poetry import Poetry
-from .repositories.pypi_repository import PyPiRepository
+from poetry.locations import CONFIG_DIR
+from poetry.packages.locker import Locker
+from poetry.packages.project_package import ProjectPackage
+from poetry.plugins.plugin_manager import PluginManager
+from poetry.poetry import Poetry
+from poetry.repositories.pypi_repository import PyPiRepository
 
 
 if TYPE_CHECKING:

poetry/masonry/builders/editable.py

-from __future__ import unicode_literals
-
 import hashlib
 import os
 import shutil

tests/console/commands/test_export.py

-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
 import pytest
 
 from tests.helpers import get_package

tests/fixtures/directory/project_with_transitive_directory_dependencies/setup.py

-# -*- coding: utf-8 -*-
 from distutils.core import setup
 
 packages = ["project_with_extras"]

tests/fixtures/git/github.com/demo/demo/setup.py

-# -*- coding: utf-8 -*-
 from setuptools import setup
 
 

tests/fixtures/git/github.com/demo/no-dependencies/setup.py

-# -*- coding: utf-8 -*-
 from setuptools import setup
 
 

tests/fixtures/git/github.com/demo/no-version/setup.py

-# -*- coding: utf-8 -*-
 import ast
 import os
 

tests/fixtures/git/github.com/demo/non-canonical-name/setup.py

-# -*- coding: utf-8 -*-
 from setuptools import setup
 
 

tests/fixtures/project_with_setup/setup.py

-# -*- coding: utf-8 -*-
-
 from setuptools import setup
 
 

tests/installation/test_executor.py

-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
 import json
 import re
 import shutil

tests/installation/test_installer.py

-from __future__ import unicode_literals
-
 import itertools
 import json
 

tests/installation/test_installer_old.py

-from __future__ import unicode_literals
-
 import itertools
 
 from pathlib import Path

tests/masonry/builders/test_editable_builder.py

-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
 import os
 import shutil
 

tests/test_factory.py

-# -*- coding: utf-8 -*-
-from __future__ import absolute_import
-from __future__ import unicode_literals
-
 from pathlib import Path
 
 import pytest

tests/utils/fixtures/setups/ansible/setup.py

-from __future__ import print_function
-
 import json
 import os
 import os.path

tests/utils/fixtures/setups/flask/setup.py

 #!/usr/bin/env python
-# -*- coding: utf-8 -*-
 import io
 import re
 from collections import OrderedDict

tests/utils/fixtures/setups/pendulum/setup.py

-# -*- coding: utf-8 -*-
 from distutils.core import setup
 
 from build import *