fix(renovate): use regexManagers (deprecated key) to avoid merge conflict

The config:best-practices preset uses regexManagers internally.
Using customManagers may cause a merge issue where our entries
get dropped. Switch to regexManagers + fileMatch for compatibility.

renovate.json

@@ -1,32 +1,26 @@
 {
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
-  "customManagers": [
+  "regexManagers": [
     {
-      "customType": "regex",
       "description": "Track SABnzbd version in Dockerfile",
-      "managerFilePatterns": ["/^Dockerfile$/"],
+      "fileMatch": ["^Dockerfile$"],
       "matchStrings": ["SABNZBD_VERSION=(?<currentValue>[0-9\\.]+)"],
       "depNameTemplate": "sabnzbd/sabnzbd",
-      "datasourceTemplate": "github-releases",
-      "versioningTemplate": "semver"
+      "datasourceTemplate": "github-releases"
     },
     {
-      "customType": "regex",
       "description": "Track Tini version in Dockerfile",
-      "managerFilePatterns": ["/^Dockerfile$/"],
+      "fileMatch": ["^Dockerfile$"],
       "matchStrings": ["\"TINI_VERSION\"\\s+\"v?(?<currentValue>[0-9\\.]+)\""],
       "depNameTemplate": "krallin/tini",
-      "datasourceTemplate": "github-releases",
-      "versioningTemplate": "semver"
+      "datasourceTemplate": "github-releases"
     },
     {
-      "customType": "regex",
       "description": "Track par2cmdline version in Dockerfile",
-      "managerFilePatterns": ["/^Dockerfile$/"],
+      "fileMatch": ["^Dockerfile$"],
       "matchStrings": ["PAR2CMDLINE_VERSION=v?(?<currentValue>[\\w\\.-]+)"],
       "depNameTemplate": "jkansanen/par2cmdline-mt",
-      "datasourceTemplate": "github-tags",
-      "versioningTemplate": "semver-coerced"
+      "datasourceTemplate": "github-tags"
     }
   ]
 }