refactor: derive __version__ from package metadata (single source)

Signed-off-by: disqualifier <dev@disqualifier.me>

src/aioweb_tls/__init__.py

@@ -7,8 +7,15 @@ tls-fingerprinting backends for aioweb - see README for usage and the extras con
         resp = await s.request_with_retries("GET", url)
 """
 
+from importlib.metadata import version, PackageNotFoundError
+
 from .session import TLSSession
 from .backends import CurlCffi, Noble
 from .protocol import TLSBackend
 
+try:
+    __version__ = version("aioweb_tls")
+except PackageNotFoundError:
+    __version__ = "0.0.0+unknown"
+
 __all__ = ["TLSSession", "CurlCffi", "Noble", "TLSBackend"]