chore(release): bump to 3.1.1 and sync pyproject.toml

Run via .hooks/sync_version.py after merging origin/main (now at 3.1.0
from lelia's purl PR). Keeps pyproject.toml and socketdev/version.py
in lockstep, as flagged in code review.

Author: flowstate

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "socketdev"
-version = "3.1.0"
+version = "3.1.1"
 requires-python = ">= 3.9"
 dependencies = [
     'requests',

socketdev/version.py

@@ -1 +1 @@
-__version__ = "3.1.0"
+__version__ = "3.1.1"