setting up for first release

Signed-off-by: Tim Bray <tbray@textuality.com>

.github/workflows/release.yaml

@@ -0,0 +1,60 @@
+name: Release
+
+on:
+  # release will only be created when ref is a tag starting with "v"
+  push:
+    tags:
+      - "v*"
+
+  workflow_dispatch:
+    inputs:
+      tag:
+        required: true
+        type: string
+        description: Use this existing Git tag to create the release
+
+jobs:
+  release:
+    name: Create Release
+    timeout-minutes: 10
+    strategy:
+      matrix:
+        go-version: ["1.19"]
+        platform: ["ubuntu-latest"]
+    runs-on: ${{ matrix.platform }}
+    env:
+      TAG: ${{ github.event.inputs.tag }}
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c
+        with:
+          fetch-depth: 0
+          ref: "main"
+
+      - name: Get short TAG
+        if: ${{ github.event_name != 'workflow_dispatch' }}
+        run: |
+            echo "Retrieving tag from Github ref"
+            echo "TAG=$(basename "${{ github.ref }}")" >> $GITHUB_ENV
+
+      - name: Create CHANGELOG for Release (tag)
+        env:
+          IMAGE: quay.io/git-chglog/git-chglog
+          # https://quay.io/repository/git-chglog/git-chglog from tag v0.14.2
+          IMAGE_SHA: 998e89dab8dd8284cfff5f8cfb9e9af41fe3fcd4671f2e86a180e453c20959e3
+        run: |
+          # generate CHANGELOG for this Github release tag only
+          echo "Using tag $TAG to create release notes"
+          docker run --rm -v $PWD:/workdir ${IMAGE}@sha256:${IMAGE_SHA} -o RELEASE_CHANGELOG.md $TAG
+
+          # send to job summary
+          cat RELEASE_CHANGELOG.md >> $GITHUB_STEP_SUMMARY
+
+      - name: Create Github Release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          echo "Using tag $TAG to create release"
+          gh release create -F RELEASE_CHANGELOG.md ${TAG} LICENSE README.md
+