feat(project): Add GitHub Actions testing workflow

GitHub actions is a workflow engine.
This testing workflow will
- keep everything inside GitHub (one platform)
- reduce dependency to an external service (TravisCI)
- introduce stricter testing (next to unit tests, staticcheck, fmt, vet)

.github/workflows/testing.yml

@@ -0,0 +1,50 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  test:
+    name: Test and lint
+    strategy:
+      matrix:
+        go-version: [
+          1.9.x,
+          1.10.x,
+          1.11.x,
+          1.12.x,
+          1.13.x,
+          1.14.x
+        ]
+        platform: [ubuntu-latest, windows-latest]
+    runs-on: ${{ matrix.platform }}
+
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-go@v2
+        with:
+          go-version: 1.14
+
+      # Caching go modules to speed up the run
+      - uses: actions/cache@v1
+        with:
+          path: ~/go/pkg/mod
+          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-go-
+
+      - name: Run go fmt
+        if: runner.os != 'Windows'
+        run: diff -u <(echo -n) <(gofmt -d -s .)
+
+      - name: Run go vet
+        run: make vet
+
+      - name: Run staticcheck
+        run: make staticcheck
+
+      - name: Run Unit tests.
+        run: make test