chore: added php 7.3-7.4 compatibility checker

[arzola]

This PR adds an extra check to ensure our codebase doesn't have any deprecated or non compatible function within our supported PHP versions

https://github.com/pressbooks/private/issues/815

[private-packagist]

composer.lock

Package changes

Package	Operation	From	To	Changes
phpcompatibility/php-compatibility	add	-	9.3.5	view code
squizlabs/php_codesniffer	add	-	3.5.8	view code

Dev Package changes

Package	Operation	From	To	Changes
phpcompatibility/php-compatibility	remove	9.3.5	-	-
squizlabs/php_codesniffer	remove	3.5.8	-	-

---

Settings · Docs · Powered by Private Packagist

[private-packagist]

The composer.lock diff comment has been updated to reflect new changes in this PR.

[codecov]

Codecov Report

Merging #976 (6cf19da) into dev (c7706d5) will not change coverage.
The diff coverage is n/a.

❗ Current head 6cf19da differs from pull request most recent head 03c4797. Consider uploading reports for the commit 03c4797 to get more accurate results

@@           Coverage Diff           @@
##              dev     #976   +/-   ##
=======================================
  Coverage   47.20%   47.20%           
=======================================
  Files           4        4           
  Lines         500      500           
=======================================
  Hits          236      236           
  Misses        264      264           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c7706d5...03c4797. Read the comment docs.