Codesniffer: remove PHP 7.0 and 7.1 support (#40174)

* Update supported versions

* Get script artifacts

* Update docs

* Remove rule redundant to PHPCompatibility.FunctionDeclarations.RemovedImplicitlyNullableParam.Deprecated

* Update tests

* Add changelog

* Add LC_ALL

* Adjust shebang

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/11844724024

Upstream-Ref: Automattic/jetpack@8ee1c37

composer.json

@@ -5,12 +5,12 @@
 	"license": "GPL-2.0-or-later",
 	"require": {
 		"php": ">=7.2",
-		"automattic/jetpack-connection": "^6.0.0",
-		"automattic/jetpack-sync": "^4.0.0"
+		"automattic/jetpack-connection": "^6.0.0-alpha",
+		"automattic/jetpack-sync": "^4.0.0-alpha"
 	},
 	"require-dev": {
 		"yoast/phpunit-polyfills": "^1.1.1",
-		"automattic/jetpack-changelogger": "^5.0.0",
+		"automattic/jetpack-changelogger": "^5.0.0-alpha",
 		"automattic/wordbless": "dev-master"
 	},
 	"suggest": {