Enhancement: Use Php73 rule set

[localheinz]

This pull request

• uses the Php73 rule set
• runs make coding-standards

[codecov]

Codecov Report

Merging #846 (c8a4ab2) into main (2067126) will not change coverage.
The diff coverage is 82.92%.

@@            Coverage Diff            @@
##               main     #846   +/-   ##
=========================================
  Coverage     83.81%   83.81%           
  Complexity       59       59           
=========================================
  Files             4        4           
  Lines           278      278           
=========================================
  Hits            233      233           
  Misses           45       45           

Impacted Files	Coverage Δ
src/Version.php	0.00% <0.00%> (ø)
src/Command/NormalizeCommand.php	90.32% <86.84%> (ø)
src/NormalizePlugin.php	64.28% <100.00%> (ø)

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