CS update after upstream changes

[jrfnl]

PHPCS ruleset: update ruleset for upstream changes

• Fix the name and description to prevent confusion between the project ruleset and the organisation ruleset.
• Set the minimum PHP version for the PHPCompatibility standard.
• Don't require property type declarations.
• Ensure special characters used as literals in an exclude pattern are escaped.

CS: no whitespace before return type colon

CS: blank line between different use statement types

CS: miscellaneous other whitespace fixes

[jrfnl]

The build failure is unrelated to this PR. See my other PRs. Happy to rebase after those have been merged.

[jaapio]

These changes look good to me. I need to have a look at the psalm failures. But this one is good to go!