Use uv for our Dockerfile

[ethanholz]

This pull request includes changes to the Dockerfile to improve the setup and execution of the application. The most important changes include switching to using uv for dependency management and modifying the way the application is copied and installed.

Improvements to Dockerfile setup:

• Added COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /bin/ to include uv in the image.
• Replaced RUN mkdir app and COPY . /app with ADD . /app to simplify the copying process.
• Changed RUN pip install --no-cache-dir /app to RUN uv sync --frozen to use uv for installing dependencies.

Improvements to application execution:

• Updated the CMD from ["python", "/app/src/gha_runner/"] to ["uv", "run", "-m", "gha_runner"] to run the application using uv.

By default, the pip command remains accessible, but incorporating the uv.lock ensures repeatability, particularly since the container is constructed with each execution of the action (for the time being). This has been verified locally through the creation of a Docker image on my personal computer. However, I intend to merge this change to facilitate testing. If the implementation proves unsuccessful, reverting this commit is acceptable.

Should the implementation be successful, we can develop documentation outlining the modifications required to maintain the lockfile in sync with new releases.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.73%. Comparing base (8c1b869) to head (57b7c20).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #40   +/-   ##
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  Coverage   94.73%   94.73%           
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  Files           3        3           
  Lines         304      304           
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  Hits          288      288           
  Misses         16       16           

Flag	Coverage Δ
unittests	94.73% <ø> (ø)

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[dwhswenson]

Treating this as a trial run, so this works for me. We can use this as a trial to see how uv works for us.