Update renovate.json

Author: ctreffs

renovate.json

@@ -64,6 +64,7 @@
   "customManagers": [
     {
       "customType": "regex",
+      "description": "Update swift-tools-version in Package.swift",
       "fileMatch": [
         "Package\\.swift"
       ],
@@ -73,6 +74,17 @@
       "datasourceTemplate": "github-releases",
       "depNameTemplate": "swiftlang/swift",
       "extractVersionTemplate": "^swift-(?<version>.*)-RELEASE$"
+    },
+    {
+      "customType": "regex",
+      "description": "Update .swift-version",
+      "fileMatch": ".swift-version",
+      "matchStrings": [
+        "(?<currentValue>.*)"
+      ],
+      "datasourceTemplate": "github-releases",
+      "depNameTemplate": "swiftlang/swift",
+      "extractVersionTemplate": "^swift-(?<version>.*)-RELEASE$"
     }
   ],
   "labels": [