Fix version number

jupyterlite_xeus_python/_version.py

@@ -1,22 +1,21 @@
 import json
+import sys
 from pathlib import Path
 
 __all__ = ["__version__"]
 
 
 def _fetchVersion():
-    HERE = Path(__file__).parent.resolve()
+    prefix = Path(sys.prefix)
+    package = prefix / "share" / "jupyter" / "labextensions" / "@jupyterlite" / "xeus-python-kernel" / "package.json"
 
-    try:
-        with open(HERE / "package.json", "r") as f:
-            version = json.load(f)["version"]
-            return (
-                version.replace("-alpha.", "a")
-                .replace("-beta.", "b")
-                .replace("-rc.", "rc")
-            )
-    except FileNotFoundError:
-        pass
+    with open(package, "r") as f:
+        version = json.load(f)["version"]
+        return (
+            version.replace("-alpha.", "a")
+            .replace("-beta.", "b")
+            .replace("-rc.", "rc")
+        )
 
 
 __version__ = _fetchVersion()