Onboard Renovate for Develocity plugin and Gradle wrapper upgrades

Adds .github/renovate.json5 so this repo manages its own Develocity
Gradle plugin version (across the workflow YAML, build-scan.ts, the
setup-gradle docs, the sample settings.gradle / build.gradle files,
and the init-script test groovy files) and Gradle wrapper bumps in the
five sample directories that previously had wrappers maintained
externally.

Renovate is scoped narrowly via enabledManagers so it does not overlap
with the npm, github-actions, and Maven-coordinate Gradle updates that
Dependabot continues to handle through .github/dependabot.yml.

.github/renovate.json5

@@ -0,0 +1,78 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  extends: [
+    "config:recommended",
+    "github>gradle/renovate-agent//presets/dv-automerge-minor.json5",
+    ":disableDependencyDashboard",
+  ],
+  // Renovate is scoped narrowly here: only the Develocity Gradle plugin (custom regex)
+  // and the Gradle wrappers in selected sample directories.
+  // Everything else (npm, github-actions, Maven coordinates) is managed by Dependabot
+  // via .github/dependabot.yml.
+  enabledManagers: ["custom.regex", "gradle-wrapper"],
+  "gradle-wrapper": {
+    fileMatch: [
+      "^\\.github/workflow-samples/gradle-plugin/gradle/wrapper/gradle-wrapper\\.properties$",
+      "^\\.github/workflow-samples/groovy-dsl/gradle/wrapper/gradle-wrapper\\.properties$",
+      "^\\.github/workflow-samples/java-toolchain/gradle/wrapper/gradle-wrapper\\.properties$",
+      "^\\.github/workflow-samples/kotlin-dsl/gradle/wrapper/gradle-wrapper\\.properties$",
+      "^\\.github/workflow-samples/non-executable-wrapper/gradle/wrapper/gradle-wrapper\\.properties$",
+      "^sources/test/init-scripts/gradle/wrapper/gradle-wrapper\\.properties$",
+    ],
+  },
+  customManagers: [
+    {
+      customType: "regex",
+      description: "Bump Develocity Gradle plugin references in files outside Dependabot's coverage",
+      fileMatch: [
+        "^\\.github/workflows/integ-test-inject-develocity\\.yml$",
+        "^sources/src/develocity/build-scan\\.ts$",
+        "^docs/setup-gradle\\.md$",
+        "(^|/)settings\\.gradle$",
+        "(^|/)settings\\.gradle\\.kts$",
+        "(^|/)build\\.gradle$",
+        "(^|/)build\\.gradle\\.kts$",
+        "^sources/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/BaseInitScriptTest\\.groovy$",
+        "^sources/test/init-scripts/src/test/groovy/com/gradle/gradlebuildaction/TestBuildResultRecorder\\.groovy$",
+      ],
+      // Patterns capture any X.Y(.Z) version. The packageRules below filter to
+      // just the current 4.x line and skip the pinned 3.x legacy refs.
+      // When the plugin's major version changes, edit `matchCurrentVersion` and
+      // `allowedVersions` in the packageRules block below — no regex edits here.
+      matchStrings: [
+        "plugin-version:[^\\n]*'(?<currentValue>\\d+\\.\\d+(?:\\.\\d+)?)'",
+        "DEVELOCITY_PLUGIN_VERSION[^\\n]*'(?<currentValue>\\d+\\.\\d+(?:\\.\\d+)?)'",
+        "`v(?<currentValue>\\d+\\.\\d+(?:\\.\\d+)?)`\\s+of\\s+the\\s+\\[Develocity Gradle plugin",
+        "id\\s+['\"]com\\.gradle\\.develocity['\"]\\s+version\\s+['\"](?<currentValue>\\d+\\.\\d+(?:\\.\\d+)?)['\"]",
+        "id\\(['\"]com\\.gradle\\.develocity['\"]\\)\\s+version\\s+['\"](?<currentValue>\\d+\\.\\d+(?:\\.\\d+)?)['\"]",
+      ],
+      depNameTemplate: "com.gradle:develocity-gradle-plugin",
+      datasourceTemplate: "maven",
+      registryUrlTemplate: "https://plugins.gradle.org/m2",
+    },
+  ],
+  packageRules: [
+    {
+      // Skip the legacy 3.16.2 references that are intentionally pinned.
+      matchManagers: ["custom.regex"],
+      matchPackageNames: ["com.gradle:develocity-gradle-plugin"],
+      matchCurrentVersion: "<4.0.0",
+      enabled: false,
+    },
+    {
+      // Current 4.x line. To start tracking the next major (5.x), replace `5.0.0`
+      // with `6.0.0` in both fields below — no regex edits needed.
+      matchManagers: ["custom.regex"],
+      matchPackageNames: ["com.gradle:develocity-gradle-plugin"],
+      matchCurrentVersion: ">=4.0.0 <5.0.0",
+      allowedVersions: "<5.0.0",
+      groupName: "Develocity Gradle plugin",
+      groupSlug: "develocity-gradle-plugin",
+    },
+    {
+      matchManagers: ["gradle-wrapper"],
+      groupName: "Gradle wrappers",
+      groupSlug: "gradle-wrappers",
+    },
+  ],
+}