add Renovate CustomManger to manage maturin version

Author: aznszn

.github/renovate.json5

@@ -141,6 +141,16 @@
       packageNameTemplate: "rust-lang/rust",
       datasourceTemplate: "github-releases",
     },
+    {
+      "customType": "regex",
+      "managerFilePatterns": ["^\\.github/workflow/build-binaries\\.yml$"],
+      "matchStrings": [
+        "maturin-version:\\s*['\"]?(?<currentValue>[\\w\\.\\-]+)['\"]?"
+      ],
+      "depNameTemplate": "maturin",
+      "packageNameTemplate": "PyO3/maturin",
+      "datasourceTemplate": "github-releases"
+    }
   ],
   vulnerabilityAlerts: {
     commitMessageSuffix: "",