add dimension to pageviews

Author: LWinterberg

src/assets/js/matomoTracking.js

@@ -6,6 +6,7 @@ const getCookie = (name) => {
 
 var _paq = (window._paq = window._paq || []);
 /* tracker methods like "setCustomDimension" should be called before "trackPageView" */
+_paq.push(['setCustomDimension', 1, import.meta.env.BRANCH]); // ab-branch
 _paq.push(["trackPageView"]);
 _paq.push(["enableLinkTracking"]);