Update CI and test things

[phil-davis]

1. phpunit reports:
   Warning: Your XML configuration validates against a deprecated schema.
   Suggestion: Migrate your XML configuration using "--migrate-configuration"!

Done with:

./vendor/phpunit/phpunit/phpunit  --configuration tests/phpunit.xml --migrate-configuration

2. Update the php-cs-fixer minor version to the current one. That is what runs today and passes. It is sometimes handy to know what is the latest that was passing.

[codecov]

Codecov Report

Merging #100 (57c8719) into master (f6f0fc5) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #100   +/-   ##
=======================================
  Coverage   97.72%   97.72%           
=======================================
  Files           1        1           
  Lines         176      176           
=======================================
  Hits          172      172           
  Misses          4        4           

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