Relax numpy constraint to allow numpy 2 (#88)

We don't have a version constraint for various other dependencies, and
having this constraint causes a build failure in the nixpkgs build of
this package: NixOS/nixpkgs#369935

After removing this constraint, we get numpy2, and the program still
runs and OCRs stuff, so it seems like it works fine?

Happy to test anything else too of course if there's any specific
worries about something numpy2 might break

pyproject.toml

@@ -17,7 +17,7 @@ dependencies = [
     "fugashi",
     "jaconv",
     "loguru",
-    "numpy<2",
+    "numpy",
     "Pillow>=10.0.0",
     "pyperclip",
     "torch>=1.0",