.github/workflows: Add a release workflow for creating draft releases

Add a GHA release workflow that's triggered on tags that's responsible
for building and pushing multi-arch (i.e. manifestlist) OLM container
images using goreleaser.

Goreleaser will also create a draft release, and generate a changelog
since the previous tag.

Rendering the release quickstart manifests is done after goreleaser has
created this draft release as there's no easy way to hook this
functionality into goreleaser after the docker images/manifestlists have
been pushed but before release artifacts are generated.

Use the 'softprops/action-gh-release' to update the newly created draft
release with these quickstart manifests as assets.

Signed-off-by: timflannagan <[email protected]>

Author: timflannagan

Diff for: .github/workflows/goreleaser.yaml

@@ -0,0 +1,56 @@
+name: release
+on:
+  pull_request:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.16
+
+      - name: Get the image tag
+        run: |
+          # Source: https://github.community/t/how-to-get-just-the-tag-name/16241/32
+          if [[ $GITHUB_REF == refs/tags/* ]]; then
+            echo IMAGE_TAG="${GITHUB_REF#refs/tags/}" >> $GITHUB_ENV
+          fi
+
+      - name: Docker Login
+        uses: docker/login-action@v1
+        with:
+          registry: quay.io
+          username: ${{ secrets.QUAY_USERNAME }}
+          password: ${{ secrets.QUAY_PASSWORD }}
+
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v2
+        with:
+          version: latest
+          args: release --rm-dist
+        env:
+          GITHUB_TOKEN: ${{ secrets.GORELEASER_GITHUB_TOKEN }}
+          IMAGE_REPO: ${{ secrets.QUAY_USERNAME }}/olm
+          PKG: github.com/operator-framework/operator-lifecycle-manager
+
+      - name: Generate quickstart release manifests
+        run: make release ver=${{ env.IMAGE_TAG }} IMAGE_REPO=quay.io/${{ secrets.QUAY_USERNAME }}/olm
+
+      - name: Update release artifacts with rendered Kubernetes manifests
+        uses: softprops/action-gh-release@v1
+        with:
+          name: ${{ env.IMAGE_TAG }}
+          files: |
+            deploy/upstream/quickstart/crds.yaml
+            deploy/upstream/quickstart/olm.yaml
+          draft: true
+          token: ${{ secrets.GORELEASER_GITHUB_TOKEN }}