Add dependabot config for GitHub Actions and Go modules (#1062)

* Add dependabot config for GitHub Actions and Go modules

Enable automated version updates for:
- github-actions: bumps pinned SHA refs with version comments
- gomod: Go module dependency updates (mirrors existing UI config)

Signed-off-by: Fiachra Corcoran <fiachra.corcoran@est.tech>

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Fiachra Corcoran <fiachra.corcoran@est.tech>

* Add license comments to dependabot.yml

Add licensing information and update dependabot configuration.

---------

Signed-off-by: Fiachra Corcoran <fiachra.corcoran@est.tech>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: efiacor

.github/dependabot.yml

@@ -0,0 +1,40 @@
+# Copyright 2026 The kpt Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    commit-message:
+      prefix: "ci"
+  - package-ecosystem: gomod
+    directory: /
+    schedule:
+      interval: weekly
+    commit-message:
+      prefix: "deps"
+  - package-ecosystem: gomod
+    directory: /docs
+    schedule:
+      interval: weekly
+    commit-message:
+      prefix: "deps"
+  - package-ecosystem: gomod
+    directory: /examples/apps/hello-server
+    schedule:
+      interval: weekly
+    commit-message:
+      prefix: "deps"