Migrate from Travis to GHA

.github/workflows/ci.yml

@@ -0,0 +1,39 @@
+name: Build and Test
+
+on: [push, pull_request]
+
+jobs:
+  build-test:
+    runs-on: ubuntu-18.04
+    container: racket/racket-ci:latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        vm: ['regular', 'CS']
+
+    steps:
+    - uses: actions/checkout@master
+    - uses: Bogdanp/setup-racket@v0.10
+      with:
+        architecture: 'x64'
+        distribution: 'minimal'
+        variant: ${{ matrix.vm }}
+        version: 'current'
+    - name: Install and setup
+      run: |
+        raco pkg install --auto compiler-lib
+        raco pkg install --auto -i --no-setup --skip-installed racket-test
+        raco setup --pkgs racket-test
+        raco pkg install --auto -i --no-setup --skip-installed compatibility-test
+        racket -l- pkg/dirs-catalog --link --check-metadata pkgs-catalog .
+        echo file://`pwd`/pkgs-catalog/ > catalog-config.txt
+        raco pkg config catalogs >> catalog-config.txt
+        raco pkg config --set catalogs `cat catalog-config.txt`
+        raco pkg update -i --auto --no-setup compatibility-lib/ compatibility-test/
+        raco setup --pkgs compatibility-lib compatibility-test
+    - name: Run tests
+      run: |
+        raco test -e -l tests/mzlib/test
+        raco test -e -l tests/racket/package
+        raco test -e -l tests/racket/package-arrows