Update php Docker tag to v8.3.8

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
php	stage	patch	8.3.7-alpine -> 8.3.8-alpine

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (eefc438) to head (94349ca).

Additional details and impacted files

@@             Coverage Diff             @@
##                main      #171   +/-   ##
===========================================
  Coverage     100.00%   100.00%           
  Complexity         3         3           
===========================================
  Files              3         3           
  Lines             17        17           
===========================================
  Hits              17        17           

Flag	Coverage Δ
unittests	100.00% <ø> (ø)

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