Update Composer dependencies (2019-08-14)

[danielbachhuber]

Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 4 installs, 24 updates, 1 removal
  - Removing symfony/contracts (v1.1.0)
  - Updating wp-coding-standards/wpcs (2.1.0 => 2.1.1): Loading from cache
  - Updating sebastian/exporter (3.1.0 => 3.1.1): Loading from cache
  - Updating phpunit/php-timer (2.1.1 => 2.1.2): Loading from cache
  - Updating theseer/tokenizer (1.1.2 => 1.1.3): Loading from cache
  - Updating phpunit/php-token-stream (3.0.1 => 3.1.0): Loading from cache
  - Updating symfony/polyfill-ctype (v1.11.0 => v1.12.0): Loading from cache
  - Updating phpspec/prophecy (1.8.0 => 1.8.1): Loading from cache
  - Updating myclabs/deep-copy (1.9.1 => 1.9.3): Loading from cache
  - Updating phpunit/phpunit (7.5.11 => 7.5.14): Loading from cache
  - Installing symfony/event-dispatcher-contracts (v1.1.5): Loading from cache
  - Updating symfony/event-dispatcher (v4.2.8 => v4.3.3): Loading from cache
  - Updating symfony/class-loader (v3.4.27 => v3.4.30): Loading from cache
  - Updating symfony/filesystem (v4.2.8 => v4.3.3): Loading from cache
  - Updating symfony/config (v4.2.8 => v4.3.3): Loading from cache
  - Installing symfony/service-contracts (v1.1.5): Loading from cache
  - Installing symfony/polyfill-php73 (v1.12.0): Loading from cache
  - Updating symfony/polyfill-mbstring (v1.11.0 => v1.12.0): Loading from cache
  - Updating symfony/console (v4.2.8 => v4.3.3): Loading from cache
  - Updating symfony/dependency-injection (v4.2.8 => v4.3.3): Loading from cache
  - Installing symfony/translation-contracts (v1.1.5): Loading from cache
  - Updating symfony/translation (v4.2.8 => v4.3.3): Loading from cache
  - Updating symfony/yaml (v4.2.8 => v4.3.3): Loading from cache
  - Updating symfony/css-selector (v3.4.27 => v3.4.30): Loading from cache
  - Updating symfony/dom-crawler (v4.2.8 => v4.3.3): Loading from cache
  - Updating symfony/browser-kit (v4.2.8 => v4.3.3): Loading from cache
  - Updating ralouphie/getallheaders (2.0.5 => 3.0.3): Loading from cache
  - Updating guzzlehttp/psr7 (1.5.2 => 1.6.1): Loading from cache
  - Updating pantheon-systems/pantheon-wordpress-upstream-tests dev-master (ef6b222 => 2f25dde):  Checking out 2f25ddefdd
symfony/event-dispatcher-contracts suggests installing psr/event-dispatcher
Writing lock file
Generating autoload files
PHP CodeSniffer Config installed_paths set to ../../wp-coding-standards/wpcs

[danielbachhuber]

Closing in favor of #418