OP-4 adds github actions build

.github/CODEOWNERS

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+@ @BitBagCommerce
+* @Sylius/core-team

.github/workflows/build.yml

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+name: Build
+
+on:
+  push:
+    branches-ignore:
+      - 'dependabot/**'
+  pull_request: ~
+  release:
+    types: [created]
+  schedule:
+    -
+      cron: "0 1 * * 6" # Run at 1am every Saturday
+  workflow_dispatch: ~
+
+jobs:
+  tests:
+    runs-on: ubuntu-18.04
+
+    name: "Sylius ${{ matrix.sylius }}, PHP ${{ matrix.php }}, Symfony ${{ matrix.symfony }}, MySQL ${{ matrix.mysql }}"
+
+    strategy:
+      fail-fast: false
+      matrix:
+        php: ["7.4"]
+        symfony: ["^4.4", "^5.2"]
+        sylius: ["~1.9.0", "~1.10.0"]
+        node: ["10.x"]
+        mysql: ["8.0"]
+
+        exclude:
+          - sylius: ~1.9.0
+            php: 8.0
+
+          - sylius: ~1.10.0
+            symfony: 4.4
+
+    env:
+      APP_ENV: test
+      DATABASE_URL: "mysql://root:root@127.0.0.1/sylius?serverVersion=${{ matrix.mysql }}"
+
+    steps:
+      -
+        uses: actions/checkout@v2
+
+      -
+        name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: "${{ matrix.php }}"
+          extensions: intl
+          tools: symfony
+          coverage: none
+
+      -
+        name: Setup Node
+        uses: actions/setup-node@v1
+        with:
+          node-version: "${{ matrix.node }}"
+
+      -
+        name: Shutdown default MySQL
+        run: sudo service mysql stop
+
+      -
+        name: Setup MySQL
+        uses: mirromutth/mysql-action@v1.1
+        with:
+          mysql version: "${{ matrix.mysql }}"
+          mysql root password: "root"
+
+      -
+        name: Output PHP version for Symfony CLI
+        run: php -v | head -n 1 | awk '{ print $2 }' > .php-version
+
+      -
+        name: Install certificates
+        run: symfony server:ca:install
+
+      -
+        name: Get Composer cache directory
+        id: composer-cache
+        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      -
+        name: Cache Composer
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          key: ${{ runner.os }}-php-${{ matrix.php }}-composer-${{ hashFiles('**/composer.json **/composer.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-php-${{ matrix.php }}-composer-
+
+      -
+        name: Restrict Symfony version
+        if: matrix.symfony != ''
+        run: |
+          composer global require --no-progress --no-scripts --no-plugins "symfony/flex:^1.10"
+          composer config extra.symfony.require "${{ matrix.symfony }}"
+
+      -
+        name: Restrict Sylius version
+        if: matrix.sylius != ''
+        run: composer require "sylius/sylius:${{ matrix.sylius }}" --no-update --no-scripts --no-interaction
+
+      -
+        name: Install PHP dependencies
+        run: composer install --no-interaction --no-scripts
+
+      -
+        name: Get Yarn cache directory
+        id: yarn-cache
+        run: echo "::set-output name=dir::$(yarn cache dir)"
+
+      -
+        name: Cache Yarn
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.yarn-cache.outputs.dir }}
+          key: ${{ runner.os }}-node-${{ matrix.node }}-yarn-${{ hashFiles('**/package.json **/yarn.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-node-${{ matrix.node }}-yarn-
+
+      -
+        name: Install JS dependencies
+        run: (cd tests/Application && yarn install)
+
+      -
+        name: Prepare test application database
+        run: |
+          (cd tests/Application && bin/console doctrine:database:create -vvv)
+          (cd tests/Application && bin/console doctrine:schema:create -vvv)
+
+      -
+        name: Prepare test application assets
+        run: |
+          (cd tests/Application && bin/console assets:install public -vvv)
+          (cd tests/Application && yarn build)
+
+      -
+        name: Prepare test application cache
+        run: (cd tests/Application && bin/console cache:warmup -vvv)
+
+      -
+        name: Load fixtures in test application
+        run: (cd tests/Application && bin/console sylius:fixtures:load -n)
+
+      -
+        name: Validate composer.json
+        run: composer validate --ansi --strict
+
+      -
+        name: Validate database schema
+        run: (cd tests/Application && bin/console doctrine:schema:validate)
+
+      -
+        name: Run PHPStan
+        run: vendor/bin/phpstan analyse -l 1 src/
+
+      -
+        name: Run PHPSpec
+        run: vendor/bin/phpspec run --ansi -f progress --no-interaction
+
+      - name: Run PHPUnit
+        run: vendor/bin/phpunit