Bump PHP dependencies

[phil-davis]

Description

composer update
Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 0 installs, 9 updates, 0 removals
  - Updating symfony/polyfill-ctype (v1.17.0 => v1.18.1): Loading from cache
  - Updating symfony/serializer (v3.4.42 => v3.4.44): Downloading (100%)         
  - Updating symfony/inflector (v3.4.42 => v3.4.44): Loading from cache
  - Updating symfony/polyfill-php70 (v1.17.0 => v1.18.1): Loading from cache
  - Updating symfony/property-access (v3.4.42 => v3.4.44): Downloading (100%)         
  - Updating symfony/property-info (v3.4.42 => v3.4.44): Downloading (100%)         
  - Updating symfony/filesystem (v3.4.42 => v3.4.44): Loading from cache
  - Updating symfony/options-resolver (v3.4.42 => v3.4.44): Downloading (100%)         
  - Updating webmozart/assert (1.8.0 => 1.9.1): Loading from cache
Writing lock file
Generating autoload files

How Has This Been Tested?

CI

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.

[codecov[bot]]

Codecov Report

Merging #167 into master will not change coverage. The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #167   +/-   ##
=========================================
  Coverage     85.67%   85.67%           
  Complexity      235      235           
=========================================
  Files            36       36           
  Lines          1117     1117           
=========================================
  Hits            957      957           
  Misses          160      160           

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