Update mirror.py to a uv script (#110)

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## Summary

From my reading of the [UV
docs](https://docs.astral.sh/uv/guides/scripts/), `mirror.py` would be a
good example of a standalone script. This PR updates `mirror.py` and the
`main.yml` workflow to be a UV script and makes use of UV in the update
process.

## Test Plan

- Update the uv version (currently 0.8.4) to an older version e.g. 0.8.3
in both `pyproject.toml` and `README.md`
- Run `uv run --no-project mirror.py` to check the update process still
works as expected

.github/workflows/main.yml

@@ -16,21 +16,15 @@ jobs:
 
       - uses: actions/checkout@v4
 
-      - uses: actions/setup-python@v5
-        with:
-          python-version: "3.11"
-
-      - name: download uv
-        run: curl -LsSf https://astral.sh/uv/install.sh | sh
-
-      - run: uv pip install --system -r requirements-dev.txt
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
 
       - name: set git config
         run: |
           git config user.name "$GITHUB_ACTOR"
           git config user.email "[email protected]"
 
-      - run: python mirror.py
+      - run: uv run --no-project mirror.py
 
       - name: check for unpushed commits
         id: check_unpushed

mirror.py

@@ -1,3 +1,12 @@
+# /// script
+# requires-python = ">=3.12"
+# dependencies = [
+#   "packaging==23.1",
+#   "urllib3==2.0.5",
+# ]
+# ///
+"""Update ruff-pre-commit to the latest version of ruff."""
+
 import re
 import subprocess
 import tomllib

pyproject.toml

@@ -4,9 +4,3 @@ version = "0.0.0"
 dependencies = [
     "ruff==0.8.4",
 ]
-
-[project.optional-dependencies]
-dev = [
-    "packaging~=23.1",
-    "urllib3>=2.0.5,<3.0.0",
-]