Avoid deprecated `SiteStatsUpdate` constructor, use `SiteStatsUpdate::factory()` instead

[xSavitar]

The code here:

SemanticSignup/src/SpecialSemanticSignup.php

Line 114 in 5d9d23c

$ssUpdate = new SiteStatsUpdate( 0, 0, 0, 0, 1 );

should be updated to something like:

$ssUpdate = SiteStatsUpdate::factory( [
	'edit' =>       0,
	'articles' => 0,
	'pages' =>   0,
	'users' =>    1,
] );

Per the Wikimedia Code Search tool, this is the only repo doing this: https://codesearch.wmcloud.org/search/?q=new%20SiteStatsUpdate&i=nope&files=&excludeFiles=&repos=