chore: prepare release 5.1.7

[phil-davis]

The code changes are only things applied by the newer php-cs-fixer major version 3.
There is no behavioral change.
But I may as well release this so that the 5.1 release series is up-to-date with the 5.1 branch.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.72%. Comparing base (162d4c6) to head (916a8b5).
Report is 3 commits behind head on 5.1.

Additional details and impacted files

@@            Coverage Diff            @@
##                5.1     #133   +/-   ##
=========================================
  Coverage     99.72%   99.72%           
  Complexity      118      118           
=========================================
  Files             7        7           
  Lines           365      365           
=========================================
  Hits            364      364           
  Misses            1        1           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.