maintainers: update cstrahan's email address

lib/maintainers.nix

···
   couchemar = "Andrey Pavlov <[e-mail]>";
   cransom = "Casey Ransom <[e-mail]>";
   CrystalGamma = "Jona Stubbe <[e-mail]>";
-  cstrahan = "Charles Strahan <[e-mail]>";
+  cstrahan = "Charles Strahan <[e-mail]>";
   cwoac = "Oliver Matthews <[e-mail]>";
   DamienCassou = "Damien Cassou <[e-mail]>";
   dasuxullebt = "Christoph-Simon Senjak <[e-mail]>";