fix: resolve CI build failures

- Fix ruff configuration in pyproject.toml (moved settings to correct sections)
- Use python -m ruff for lint check to resolve PATH issues
- Added proper pip upgrade before installing dependencies

pyproject.toml

@@ -59,14 +59,11 @@ omit = ["git_commit_ai/tests/*"]
 [tool.coverage.report]
 exclude_lines = ["pragma: no cover", "def __repr__", "raise AssertionError", "raise NotImplementedError"]
 
-[tool.black]
-line-length = 100
-target-version = ['py39']
-include = '\.pyi?$'
-
-[tool.ruff.lint]
+[tool.ruff]
 line-length = 100
 target-version = "py39"
+
+[tool.ruff.lint]
 select = ["E", "F", "W", "I", "B", "C4", "UP", "ARG", "SIM"]
 ignore = ["E501", "B008", "C901"]