ci: switches release process to gh actions and goreleaser (#87)

Also preserves coveralls and appveyor. Closes #58

.github/workflows/release.yml

@@ -0,0 +1,26 @@
+name: goreleaser
+
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  goreleaser:
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.15
+      - name: Run GoReleaser
+        uses: goreleaser/goreleaser-action@v2
+        with:
+          version: latest
+          args: release --rm-dist
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/test.yml

@@ -0,0 +1,37 @@
+name: tests
+
+on:
+  pull_request:
+    types: ['opened', 'synchronize']
+    paths-ignore:
+      - 'README.md'
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - 'README.md'
+jobs:
+  unit:
+    runs-on: ubuntu-20.04
+    strategy:
+      fail-fast: true
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.15
+      - name: Run tests
+        run: |
+          make test
+      - name: Install goveralls
+        env:
+          GO111MODULE: off
+        run: go get github.com/mattn/goveralls
+      - name: Send coverage
+        env:
+          COVERALLS_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: goveralls -coverprofile=cover.out -service=github