Fix calc_constraints for older python versions

.github/workflows/build.yml

@@ -45,7 +45,7 @@ jobs:
           uvx twine check dist/*
       - name: "Install built packages"
         run: |
-          uv run .ci/scripts/calc_constraints.py -u pyproject.toml > upperbounds_constraints.txt
+          uv run --script .ci/scripts/calc_constraints.py -u pyproject.toml > upperbounds_constraints.txt
           # This seems to be the only way to inject the constraints file.
           uv pip install dist/pulp_catdog-*-py3-none-any.whl -c .ci/assets/ci_constraints.txt -c upperbounds_constraints.txt
       - name: "Generate api specs"

templates/github/.ci/scripts/calc_constraints.py.j2

@@ -1,9 +1,19 @@
 {% include 'header.j2' %}
+#!/usr/bin/env python
+# /// script
+# requires-python = ">=3.9"
+# dependencies = [
+#     "packaging>=26.0,<27",
+#     "pyyaml>=6.0.3,<6.1",
+#     "tomli;python_version<'3.11'",
+# ]
+# ///
 
 import argparse
 import fileinput
 import urllib.request
 import sys
+
 from packaging.requirements import Requirement
 from packaging.version import Version
 import yaml

templates/github/.github/workflows/build.yml.j2

@@ -37,7 +37,7 @@ jobs:
           uvx twine check dist/*
       - name: "Install built packages"
         run: |
-          uv run .ci/scripts/calc_constraints.py -u pyproject.toml > upperbounds_constraints.txt
+          uv run --script .ci/scripts/calc_constraints.py -u pyproject.toml > upperbounds_constraints.txt
           # This seems to be the only way to inject the constraints file.
           uv pip install dist/{{ plugin_name | snake }}-*-py3-none-any.whl -c .ci/assets/ci_constraints.txt -c upperbounds_constraints.txt
       - name: "Generate api specs"