Migrate Renovate config (#13)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/renovate.json

@@ -1,10 +1,14 @@
 {
-  "extends": ["config:recommended", ":dependencyDashboard"],
-  "regexManagers": [
+  "extends": [
+    "config:recommended",
+    ":dependencyDashboard"
+  ],
+  "customManagers": [
     {
-      "fileMatch": [
-        "(^|/)Dockerfile$",
-        "(^|/)Dockerfile\\.[^/]*$"
+      "customType": "regex",
+      "managerFilePatterns": [
+        "/(^|/)Dockerfile$/",
+        "/(^|/)Dockerfile\\.[^/]*$/"
       ],
       "matchStrings": [
         "#\\srenovate:\\sdatasource=(?<datasource>.*?) depName=(?<depName>.*?)( versioning=(?<versioning>.*?))?( extractVersion=(?<extractVersion>.*?))?\\s(ENV|ARG) .*?_VERSION=(?<currentValue>.*)\\s"