fix(renovate): use rangeStrategy "bump" for pep621

pep621 has no manager-specific range strategy, so "auto" resolves to
"replace". With "replace", a ">=" lower bound that already allows the
new version produces no update at all, which would make the lower
bounds added to pyproject.toml useless.

"bump" raises the lower bound in pyproject.toml and updates uv.lock in
the same PR. Checked with a local renovate dry-run on a copy with older
locked versions: "replace" proposed nothing, while "bump" proposed
boto3 >=1.43.90 -> >=1.43.102, requests >=2.33.0 -> >=2.34.2, etc.

Author: matrixise

renovate.json

@@ -6,6 +6,11 @@
     "python": "3.13"
   },
   "packageRules": [
+    {
+      "description": "Bump the '>=' lower bounds in pyproject.toml together with uv.lock. With the default 'replace' strategy a '>=' range already satisfied by the new version produces no update at all",
+      "matchManagers": ["pep621"],
+      "rangeStrategy": "bump"
+    },
     {
       "description": "Python is pinned to 3.13.x (Heroku, Docker, mise): never bump requires-python",
       "matchManagers": ["pep621"],