chore: hermetic build to manage the graalvm presubmit image versions

googleapis/sdk-platform-java#3800

Author: diegomarquezp

renovate.json

@@ -12,15 +12,6 @@
   ],
   "ignorePaths": [".kokoro/requirements.txt"],
   "customManagers": [
-    {
-      "customType": "regex",
-      "fileMatch": [
-        "^.kokoro/presubmit/graalvm-native.*.cfg$"
-      ],
-      "matchStrings": ["value: \"gcr.io/cloud-devrel-public-resources/graalvm.*:(?<currentValue>.*?)\""],
-      "depNameTemplate": "com.google.cloud:sdk-platform-java-config",
-      "datasourceTemplate": "maven"
-    },
     {
       "customType": "regex",
       "fileMatch": [