[CI] Add automated release workflow using swift-temporal-sdk (#69)

Integrate swift-temporal-sdk's reusable auto-release workflow for
automated semantic versioning releases.

### Motivation

- Automate the release process using semantic versioning labels,
reducing manual overhead and ensuring consistent versioning across
releases.

### Modifications

- Add .github/workflows/auto-release.yml that uses swift-temporal-sdk's
reusable workflow

### Result

- When PRs are merged with semver labels (semver/patch, semver/minor),
the workflow automatically creates GitHub releases. Major releases
require manual creation.

### Test Plan

- Workflow will be validated after merge by labeling PRs with semver
labels and verifying that releases are created automatically.

Author: inductor

.github/workflows/auto-release.yml

@@ -0,0 +1,12 @@
+name: Auto Release
+
+on:
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: read
+
+jobs:
+  auto-release:
+    uses: apple/swift-temporal-sdk/.github/workflows/auto-release.yml@main