Adding fetch-depth to actions/checkout to fix CI

[jamesbraza]

From this CI run, we get:

  × No solution found when resolving dependencies for split
  │ (python_full_version == '3.11.*' and platform_python_implementation ==
  │ 'PyPy'):
  ╰─▶ Because only the following versions of paper-qa are available:
          paper-qa<=5.0.0
          paper-qa==5.0.1
...
          paper-qa==5.3.2
      and paper-qa==5.3.2 depends on fhaviary, we can conclude that
      paper-qa>5.3.1 depends on fhaviary.
      And because paper-qa>=5.0.0,<=5.3.1 depends on fhaviary, we can conclude
      that paper-qa>=5.0.0 depends on fhaviary.
      And because fhaviary[paperqa] depends on paper-qa>=5 and your workspace
      requires fhaviary[paperqa], we can conclude that your workspace's
      requirements are unsatisfiable.

      hint: The package `paper-qa` depends on the package `fhaviary` but the
      name is shadowed by one of your workspace members. Consider changing the
      name of the workspace member.

This is related to our "circular" pinning with paper-qa (where paper-qa depends on fhaviary, and we have a convenience paperqa extra here). Note that paper-qa currently pins ``fhaviary[llm]>=0.8.2`.

#117 tried to fix this by downpinning uv<0.5, but that didn't work. So this PR looks closer, and realizes in this CI run's logs for uv sync --verbose:

Installed 124 packages in 121ms
...
 + fhaviary==0.1.dev1+g6ddf4a0 (from file:///home/runner/work/aviary/aviary)

This is incorrect! So this leads me to pypa/setuptools-scm#952, where I realized we ned to add fetch-depth: 0 so the correct version of fhaviary gets used in CI.

Someday after actions/checkout#1471 we can just use fetch-tags: true.

[whitead]

scooby doo level mystery