renovate: limit update to python wolfi images only to patch releases (#287)

Author: xrmx

.github/renovate.json

@@ -2,5 +2,13 @@
     "$schema": "https://docs.renovatebot.com/renovate-schema.json",
     "extends": [
         "github>elastic/renovate-config:only-chainguard"
+    ],
+    "separateMinorPatch": true,
+    "packageRules": [
+        {
+            "groupName": "python",
+            "matchUpdateTypes": ["patch"],
+            "matchPackageNames": ["wolfi/python"]
+        }
     ]
-}
+}