chore: sync .python-version with upstream sentry

Author: Copilot

.gitignore

@@ -9,3 +9,4 @@ venv
 .vscode/
 # Fetched from upstream
 tests/conftest.py
+.python-version

.python-version

@@ -6,10 +6,12 @@
 # Likewise, their root-level conftest is not provided as a pytest plugin for
 # use outside their own tests, but we need their fixtures. We fetch them into
 # our own namespace here.
+# We also sync the Python version from upstream to ensure compatibility.
 deps:
 	git submodule update --init
 	poetry run pip install -r deps/sentry/requirements-dev-frozen.txt -e deps/sentry
 	cp -f deps/sentry/tests/conftest.py tests/conftest.py
+	cp -f deps/sentry/.python-version .python-version
 
 clean:
 	rm -rf *.egg-info src/*.egg-info