Provide __version__ of the package (#279)

Provide __version__ of the package

So it can be easily checked when installed on the system.

Reviewed-by: Matej Focko

requre/__init__.py

@@ -1,6 +1,9 @@
 # Copyright Contributors to the Packit project.
 # SPDX-License-Identifier: MIT
 
+import contextlib
+from importlib.metadata import PackageNotFoundError, distribution
+
 from requre.base_testclass import RequreTestCase
 from requre.record_and_replace import record, replace
 from requre.cassette import Cassette
@@ -9,6 +12,9 @@
 from requre.helpers.files import StoreFiles
 from requre.import_system import UpgradeImportSystem
 
+with contextlib.suppress(PackageNotFoundError):
+    __version__ = distribution(__name__).version
+
 __all__ = [
     record.__name__,
     replace.__name__,