[Dependencies] Remove unused php-cs-fixer from require-dev

[dbu]

Q	A
Branch?	2.0
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	no
Tests pass?	see travis-ci
Fixed tickets	-
License	MIT
Doc PR	-

This dependency is not used since we use styleci instead (which is php-cs-fixer as a service). The cs fixer does not install with PHP 7.3, making the PHP nightly build error.

[dbu]

yay, makes nightly green!

[robfrawley]

Why was this removed?

This dependency is not used since we use styleci instead.

All contributors and/or collaborators rely on this tool to check our work before committing changes or (in my case) requiring it is run before I accept pull requests. StyleCI is a great check and allows us to express that our code style is sensible via a badge on the README.md, but no one uses its interface to apply patches or otherwise interact with the codebase (in my experience here, anyway). It becomes a nightmare to explain to everyone to install the tool (it's already a pain to get them to even run it, never mind requiring its installation). We should instead use --ignore-platform-reqs on the nightly build.

[dbu]

i was not aware that you use it. i never bother and instead rely on styleci. the build had been broken for a while and this was the easiest way to fix it that i found. i'll quickly do a pr to add it back, ignoring the platform for nightly (which seems a good idea anyways).

[dbu]

see #1045