Replace (defunct) Travis with Github Actions

.github/workflows/test.yaml

@@ -0,0 +1,28 @@
+name: Python package
+
+on: [push]
+
+jobs:
+  build:
+
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "pypy3"]
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: pip
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install -r requirements.txt
+      - name: Test with pytest
+        run: |
+          python -m unittest discover -s sacremoses/test