Remove Travis CI; use GH Actions

.github/workflows/test.yml

@@ -0,0 +1,32 @@
+name: Test
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        go-version: [1.16.x, 1.17.x]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Install go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go-version }}
+
+      - name: Check out code
+        uses: actions/checkout@v2
+
+      - name: Test
+        run: go test -count 1 -bench . -benchtime 1x ./...
+
+      - name: Test with -tags purego
+        run: go test -count 1 -bench . -benchtime 1x -tags purego ./...
+
+# TODO: Test on other architectures. Unfortunately only amd64 is supported
+# by GH Actions. We could use QEMU in the meantime.