Add GitHub Store to signatories

Author: marcprux

public/img/logos/github-store.org.png

@@ -244,6 +244,9 @@
   region: "DE"
   social-x: "https://x.com/Ghostery"
   social-linkedin: "https://linkedin.com/company/ghostery"
+- organization: "GitHub Store"
+  url: "github-store.org"
+  poc: "Usmon <rainxchzed@gmail.com>"
 - organization: "GNOME Foundation"
   url: "gnome.org"
   poc: "Maria Majadas <mmajadas@gnome.org>"