Unpin and update bpython

bpython is an alternative interactive shell,
basically lighter-weight ipython. Both can be used
for the `verdi shell` command, ipython is installed
by default, while bpython is installed via optional
'bpython' extras.

Minimum version was bumped to 0.20, which is
the first version to support python 3.9.
I've removed the upper pin, so that new versions
can naturally track new python versions. See bpython changelog:
https://github.com/bpython/bpython/blob/main/CHANGELOG.rst

Author: danielhollas

.pre-commit-config.yaml

@@ -45,7 +45,7 @@ repos:
       )$
 
 - repo: https://github.com/astral-sh/uv-pre-commit
-  rev: 0.7.6
+  rev: 0.8.0
   hooks:
     # Check and update the uv lockfile
   - id: uv-lock

pyproject.toml

@@ -214,7 +214,7 @@ atomic_tools = [
   'spglib>=1.14,<3.0'
 ]
 bpython = [
-  'bpython~=0.18.0'
+  'bpython~=0.20'
 ]
 docs = [
   'pydata-sphinx-theme~=0.15.1',