perlPackages.MozillaCA: replace outdated cacert.pem with pkgs.cacert

Mozilla::CA returns a path to a bundled cacert.pem file, this commit replaces
the bundled certificates with pkgs.cacert.

pkgs/top-level/perl-packages.nix

@@ -13120,6 +13120,11 @@ let
       url = mirror://cpan/authors/id/A/AB/ABH/Mozilla-CA-20180117.tar.gz;
       sha256 = "f2cc9fbe119f756313f321e0d9f1fac0859f8f154ac9d75b1a264c1afdf4e406";
     };
+
+    postPatch = ''
+      ln -s --force ${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt lib/Mozilla/CA/cacert.pem
+    '';
+
     meta = {
       description = "Mozilla's CA cert bundle in PEM format";
       license = stdenv.lib.licenses.mpl20;