feat(deps): add parsedown and parsedown-extra

vendor/erusev/parsedown-extra/.travis.yml

@@ -0,0 +1,30 @@
+language: php
+
+dist: trusty
+sudo: false
+
+matrix:
+  include:
+    - php: 5.3
+      dist: precise
+    - php: 5.4
+    - php: 5.5
+    - php: 5.6
+    - php: 7.0
+    - php: 7.1
+    - php: 7.2
+    - php: 7.3
+    - php: 7.4
+    - php: nightly
+  fast_finish: true
+  allow_failures:
+    - php: nightly
+    - php: hhvm-nightly
+
+install:
+  - composer install --prefer-source
+
+script:
+  - vendor/bin/phpunit
+  - vendor/bin/phpunit vendor/erusev/parsedown/test/CommonMarkTestWeak.php || true
+  - '[ -z "$TRAVIS_TAG" ] || [ "$TRAVIS_TAG" == "$(php -r "require(\"ParsedownExtra.php\"); echo ParsedownExtra::version;")" ]'