added GitHub Actions workflow

.github/workflows/coding-style.yml

@@ -0,0 +1,31 @@
+name: Coding Style
+
+on: [push, pull_request]
+
+jobs:
+    nette_cc:
+        name: Nette Code Checker
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v2
+            - uses: shivammathur/setup-php@v1
+              with:
+                  php-version: 7.4
+                  coverage: none
+
+            - run: composer create-project nette/code-checker temp/code-checker ^3 --no-progress
+            - run: php temp/code-checker/code-checker --strict-types --no-progress
+
+
+    nette_cs:
+        name: Nette Coding Standard
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v2
+            - uses: shivammathur/setup-php@v1
+              with:
+                  php-version: 7.4
+                  coverage: none
+
+            - run: composer create-project nette/coding-standard temp/coding-standard ^2 --no-progress
+            - run: php temp/coding-standard/ecs check src tests --config temp/coding-standard/coding-standard-php71.yml

.github/workflows/static-analysis.yml

@@ -0,0 +1,21 @@
+name: Static Analysis (only informative)
+
+on:
+    push:
+        branches:
+          - master
+
+jobs:
+    phpstan:
+        name: PHPStan
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v2
+            - uses: shivammathur/setup-php@v1
+              with:
+                  php-version: 7.4
+                  coverage: none
+
+            - run: composer install --no-progress --prefer-dist
+            - run: composer phpstan
+              continue-on-error: true # is only informative

.github/workflows/tests.yml

@@ -0,0 +1,58 @@
+name: Tests
+
+on: [push, pull_request]
+
+jobs:
+    tests:
+        runs-on: ubuntu-latest
+        strategy:
+            matrix:
+                php: ['7.1', '7.2', '7.3', '7.4', '8.0']
+
+            fail-fast: false
+
+        name: PHP ${{ matrix.php }} tests
+        steps:
+            - uses: actions/checkout@v2
+            - uses: shivammathur/setup-php@v2
+              with:
+                  php-version: ${{ matrix.php }}
+                  coverage: none
+
+            - run: composer install --no-progress --prefer-dist
+            - run: vendor/bin/tester tests -s -C
+            - if: failure()
+              uses: actions/upload-artifact@v2
+              with:
+                  name: output
+                  path: tests/**/output
+
+
+    lowest_dependencies:
+        name: Lowest Dependencies
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v2
+            - uses: shivammathur/setup-php@v2
+              with:
+                  php-version: 7.1
+                  coverage: none
+
+            - run: composer update --no-progress --prefer-dist --prefer-lowest --prefer-stable
+            - run: vendor/bin/tester tests -s -C
+
+
+    code_coverage:
+        name: Code Coverage
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v2
+            - uses: shivammathur/setup-php@v2
+              with:
+                  php-version: 7.4
+                  coverage: none
+
+            - run: composer install --no-progress --prefer-dist
+            - run: wget https://github.com/satooshi/php-coveralls/releases/download/v1.0.1/coveralls.phar
+            - run: vendor/bin/tester -p phpdbg tests -s -C --coverage ./coverage.xml --coverage-src ./src
+            - run: php coveralls.phar --verbose --config tests/.coveralls.yml