Enabled trusted publisher

Author: hsbt

.github/workflows/push_gem.yml

@@ -0,0 +1,46 @@
+name: Publish gem to rubygems.org
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: read
+
+jobs:
+  push:
+    if: github.repository == 'ruby/net-smtp'
+    runs-on: ubuntu-latest
+
+    environment:
+      name: rubygems.org
+      url: https://rubygems.org/gems/net-smtp
+
+    permissions:
+      contents: write
+      id-token: write
+
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@d5126b9b3579e429dd52e51e68624dda2e05be25 # v1.267.0
+        with:
+          bundler-cache: true
+          ruby-version: ruby
+
+      - name: Publish to RubyGems
+        uses: rubygems/release-gem@7f9650160c1a4e7989fdc9855807bdbd421d8b6b # v1.4.1
+
+      - name: Create GitHub release
+        run: |
+          tag_name="$(git describe --tags --abbrev=0)"
+          gh release create "${tag_name}" --verify-tag --generate-notes
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}