Added github Actions workflow for the CI

.github/workflows/ci.yml

@@ -0,0 +1,95 @@
+# This is a basic workflow to help you get started with Actions
+
+name: CI
+
+on:
+  push:
+    branches: [ main, dev ]
+  pull_request:
+    branches: [ main ]
+
+  # Allows to run this workflow manually from the Actions tab
+  workflow_dispatch:
+  
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        racket: ['6.9', '6.10', '6.10.1', '6.11', '6.12', '7.0', '7.1', '7.2', '7.3', '7.4', '7.5', '7.6', '7.7', '7.8', '7.9', '8.0']
+        cov: [true]
+        racket_cs: [0]
+        include:
+          - racket: '6.0'
+            racket_cs: 0
+            cov: false
+          - racket: '6.1'
+            racket_cs: 0
+            cov: false
+          - racket: '6.1.1'
+            racket_cs: 0
+            cov: false
+          - racket: '6.2'
+            racket_cs: 0
+            cov: false
+          - racket: '6.3'
+            racket_cs: 0
+            cov: false
+          - racket: '6.4'
+            racket_cs: 0
+            cov: false
+          - racket: '6.5'
+            racket_cs: 0
+            cov: false
+          - racket: '6.6'
+            racket_cs: 0
+            cov: false
+          - racket: '6.7'
+            racket_cs: 0
+            cov: false
+          - racket: '6.8'
+            racket_cs: 0
+            cov: false
+          - racket: '8.0'
+            racket_cs: 1
+    env:
+      # RACKET_DIR is an argument to install-racket.sh
+      RACKET_VERSION: "${{ matrix.racket }}"
+      RACKET_CS: "${{ matrix.racket_cs }}"
+      COV: "${{ matrix.cov }}"
+    steps:
+      - uses: actions/checkout@v2
+      - name: Add to $PATH
+        run: |
+          printf %s\\n "$HOME/.racket/bin" >> "$GITHUB_PATH"
+      - name: Print environment variables
+        run: |
+          echo "matrix.racket ${{ matrix.racket }}"
+          echo "matrix.racket_cs ${{ matrix.racket_cs }}"
+          echo "matrix.cov ${{ matrix.cov }}"
+          echo HOME="$HOME"
+          echo PATH="$PATH"
+          echo RACKET_VERSION="$RACKET_VERSION"
+          echo RACKET_CS="$RACKET_CS"
+          echo COV="$COV"
+          echo GITHUB_WORSPACE="$GITHUB_WORKSPACE"
+      - name: Install Racket
+        run: |
+          export RACKET_DIR="$HOME/.racket"
+          curl -L https://raw.githubusercontent.com/greghendershott/travis-racket/master/install-racket.sh | bash
+      - name: Install cover
+        run: if $COV; then raco pkg install --deps search-auto doc-coverage cover cover-codecov; fi # or cover-coveralls
+      - name: Install the Racket package
+        run: raco pkg install --deps search-auto -j 2
+      - name: Test the Racket package
+        run: raco test -r -p "$(basename "$GITHUB_WORKSPACE")"
+      - name: Check the dependencies of the Racket package
+        run: if $COV; then raco setup --check-pkg-deps --no-zo --no-launcher --no-install --no-post-install --no-docs --pkgs "$(basename "$TRAVIS_BUILD_DIR")"; fi
+      - name: Check documentation coverage
+        run: if $COV; then raco doc-coverage "$(basename "$TRAVIS_BUILD_DIR")"; fi
+      - name: Check code coverage
+        run: if $COV; then raco cover -s main -s test -s doc -f codecov -f html -d ~/coverage . || true; fi
+      # TODO: add an option to cover to run the "outer" module too, not just the submodules.
+      # TODO: deploy the coverage info.
+