Replaced Travis CI with GitHub Actions (#53)

* Replaced travis with github actions

* Added os matrix

Author: bkwi

.github/workflows/tests.yml

@@ -0,0 +1,23 @@
+name: Run Tests
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: [3.5, 3.6, 3.7, 3.8]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install requirements
+      run: pip install -r requirements.txt
+    - name: Run tests
+      run: pytest -v --cov=filestack tests