ci(renovate): Remove an unused custom manager

The custom manager is not required anymore, because the `eclipseTemurin`
version was removed from `libs.gradle.toml`.

Signed-off-by: Martin Nonnenmacher <[email protected]>

Author: mnonnenmacher

renovate.json

@@ -6,17 +6,6 @@
     ":semanticCommitScopeDisabled",
     ":semanticCommitTypeAll(deps)"
   ],
-  "customManagers": [
-    {
-      "description": "Update Eclipse Temurin in libs.versions.toml",
-      "customType": "regex",
-      "datasourceTemplate": "docker",
-      "depNameTemplate": "eclipse-temurin",
-      "managerFilePatterns": ["^gradle\\/libs\\.versions\\.toml$"],
-      "matchStrings": ["eclipseTemurin = \"(?<currentValue>[^@]+)(?:@(?<currentDigest>sha256:[a-f0-9]+))\""],
-      "versioningTemplate": "docker"
-    }
-  ],
   "dependencyDashboard": false,
   "labels": ["dependencies"],
   "packageRules": [