refactor: derive __version__ from package metadata (single source)

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

src/dpy_appemojis/__init__.py

@@ -2,6 +2,8 @@
 
 see :mod:`dpy_appemojis.dpy_appemojis` for the full module docstring, api, and error contract
 """
+from importlib.metadata import PackageNotFoundError, version
+
 from .dpy_appemojis import (
     EMOJI_DIR,
     MAX_APP_EMOJIS,
@@ -12,7 +14,10 @@ from .dpy_appemojis import (
     RefreshResult,
 )
 
-__version__ = "0.1.2"
+try:
+    __version__ = version("dpy_appemojis")
+except PackageNotFoundError:
+    __version__ = "0.0.0+unknown"
 
 __all__ = [
     "DPYAppEmojis",