refactor: use uv to resolve dependencies

This changes the project to adopting [uv](https://docs.astral.sh/uv/)
for dependency resolution. At this time, we support none of the
additional uv features other than the lockfile and then using it to
install and run the application. Using pip still works as well!

Dockerfile

@@ -1,8 +1,8 @@
 FROM python:3.10-slim
+COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /bin/
 
 ENV PYTHONUNBUFFERED=1
-RUN mkdir app
-COPY . /app
-RUN pip install --no-cache-dir /app
-
-CMD [ "python", "/app/src/gha_runner/" ]
+ADD . /app
+WORKDIR /app
+RUN uv sync --frozen # This installs the dependencies
+CMD ["uv", "run", "-m", "gha_runner"]