build: require Python 3.11 or later

pydantic-settings and validators, at the versions required, support
Python 3.11 and later only.

- Raise requires-python, drop the 3.10 classifier and move black's
  target to py311.

CHANGELOG.md

@@ -8,6 +8,7 @@ All notable changes to this project will be documented in this file.
 - Built access level labels from their bits instead of a fixed table of combinations, so a level the server adds later is labelled too. A project level (bit 16 and up) is named after the project as the server reports it to its members, e.g. `Brain/MINDS 2.0 Open`, and otherwise `Project<n> Open`. A restrict network other than CBS is `Restrict<n> Open`; `0x0200`, formerly `5Kikan Open`, is now `Restrict2 Open`.
 - `chacl` takes keys built the same way: `cbs_or_pw_open`, `project0_open` and so on. `5kikan_open` is no longer accepted. Its help lists them, an invalid level lists the projects the user belongs to with their keys, and `public` and `storage`, which the server refuses, are refused before any request.
 - `ls` asks the server for the user's projects once per run when logged in.
+- Required Python 3.11 or later, as `pydantic-settings` and `validators` do.
 - Raised the minimum version of `pydantic` to 2.14.3, and of the development tools `black`, `flake8`, `isort` and `pyright` to their current releases.
 - Removed `FolderAccessLevel.ACCESS_LEVELS` and `FolderAccessLevelItem`. `FolderSimple.access_level_label()` labels a level with the project names given to it.
 

pyproject.toml

@@ -14,13 +14,12 @@ authors = [
 ]
 license = { text = "MIT" }
 readme = "README.md"
-requires-python = ">=3.10"
+requires-python = ">=3.11"
 classifiers = [
     "Development Status :: 4 - Beta",
     "Environment :: Console",
     "Intended Audience :: Developers",
     "Intended Audience :: Science/Research",
-    "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
@@ -53,7 +52,7 @@ mdrs = "mdrsclient.__main__:main"
 
 [tool.black]
 line-length = 120
-target-version = ['py310']
+target-version = ['py311']
 include = '\.pyi?$'
 exclude = '''
 /(