add github actions CI

.github/workflows/CI.yml

@@ -0,0 +1,31 @@
+name: Run tests
+
+on: 
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        julia-version: ['1.6', '1']
+        julia-arch: [x64, x86]
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+        exclude:
+          - os: macOS-latest
+            julia-arch: x86
+        include:
+          - version: 'nightly'
+            os: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - uses: julia-actions/setup-julia@v1
+        with:
+          version: ${{ matrix.julia-version }}
+          arch: ${{ matrix.julia-arch }}
+      - uses: julia-actions/julia-buildpkg@v1
+      - uses: julia-actions/julia-runtest@v1