chore: sync renovate template from synthtool (#2601)

In this PR:
- Sync googleapis/synthtool#1921
- Sync googleapis/synthtool#1922
- Sync googleapis/synthtool#1941

Author: JoeWang1127

library_generation/owlbot/templates/java_library/renovate.json

@@ -16,6 +16,26 @@
     ".kokoro/requirements.txt",
     ".github/workflows/**"
   ],
+  "customManagers": [
+    {
+      "customType": "regex",
+        "fileMatch": [
+        "^.kokoro/presubmit/graalvm-native.*.cfg$"
+      ],
+      "matchStrings": ["value: \"gcr.io/cloud-devrel-public-resources/graalvm.*:(?<currentValue>.*?)\""],
+      "depNameTemplate": "com.google.cloud:sdk-platform-java-config",
+      "datasourceTemplate": "maven"
+    },
+    {
+      "customType": "regex",
+      "fileMatch": [
+      "^.github/workflows/unmanaged_dependency_check.yaml$"
+      ],
+      "matchStrings": ["uses: googleapis/sdk-platform-java/java-shared-dependencies/unmanaged-dependency-check@google-cloud-shared-dependencies/v(?<currentValue>.+?)\\n"],
+      "depNameTemplate": "com.google.cloud:sdk-platform-java-config",
+      "datasourceTemplate": "maven"
+    }
+  ],
   "packageRules": [
     {
       "packagePatterns": [
@@ -57,7 +77,8 @@
         "^com.google.truth:truth",
         "^org.mockito:mockito-core",
         "^org.objenesis:objenesis",
-        "^com.google.cloud:google-cloud-conformance-tests"
+        "^com.google.cloud:google-cloud-conformance-tests",
+        "^org.graalvm.buildtools:junit-platform-native"
       ],
       "semanticCommitType": "test",
       "semanticCommitScope": "deps"