chore: release via github actions

Add a `release.yml` Github Actions workflow config which automates
the build and release process of Listmonk.

.github/workflows/release.yml

@@ -0,0 +1,38 @@
+name: goreleaser
+
+on:
+  push:
+    tags:
+      - "v*" # Will trigger only if tag is pushed matching pattern `v*` (Eg: `v0.1.0`)
+
+jobs:
+  goreleaser:
+    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: Login to Docker Registry
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Prepare Dependencies
+        run: |
+          make deps
+
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v2
+        with:
+          version: latest
+          args: --parallelism 1 --rm-dist --skip-validate
+        env:
+          GITHUB_TOKEN: ${{ secrets.GORELEASER_TOKEN }}