Verify bundled deps using CI

[mvorisek]

Description

I am the author of https://github.com/php/php-src/blob/master/.github/actions/verify-generated-files/action.yml and I would be happy if this integrity concept can be extended also to all extenal/bundled deps like PCRE [1], Unicode tables [2] etc.

The expected behaviour is zero changes after the update is run. This will prevent hiding bad code and prevent human mistakes.

• [1] PCRE2 ext/pcre: update to PCRE2 v10.44 #14498
• [2] Unicode tables Update Unicode tables to 14.0.0 #7502 (comment) /w update steps described
• [3] XSSE Added zend_simd.h #18413
• [4] uriparser Update uriparser to version 0.9.9 #19711
• [5] IR 2ff7a18
• [6] timelib a0329db - https://github.com/derickr/timelib/tags
• [7] xxHash hash: Upgrade xxHash to 0.8.2 #20064

This was probably not done yet to not slow down the testing pipelines. The solution is to run the integrity verification of the external sources as a separate workflow only when the source files are changed and always in nightly.