Bump version to 0.5.1

- Update version number in pyproject.toml from 0.5.0 to 0.5.1 to
  reflect the new patch release.

This prepares the package for the next release which includes the
async detection fix and Python 3.14 CI support.

Author: kipe

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "nordpool"
-version = "0.5.0"
+version = "0.5.1"
 description = "Python library for fetching Nord Pool spot prices."
 authors = ["Kimmo Huoman <kipenroskaposti@gmail.com>"]
 license = "MIT"