mariadb-connector-c: switch links over to github

github links have slightly fresher versions.

pkgs/servers/sql/mariadb/connector-c/3_1.nix

···
 
 callPackage ./. (args // {
   version = "3.1.21";
-  hash = "sha256-PovyQvomT8+vGWS39/QjLauiGkSiuqKQpTrSXdyVyow=";
+  hash = "sha256-guN3Rcsb/EV4rxPE3yhJRSsT1+z44zUetg7ZBA4WjIc=";
 })

pkgs/servers/sql/mariadb/connector-c/3_2.nix

···
 
 callPackage ./. (args // {
   version = "3.2.7";
-  hash = "sha256-nXGWJI5ml8Ccc+Fz/psoIEX1XsnXrnQ8HrrQi56lbdo=";
+  hash = "sha256-F7s9fcbJiz6lsWrvlTpY+ZET8MPwlyWPKJZOvHEwBvo=";
 })

pkgs/servers/sql/mariadb/connector-c/3_3.nix

···
 
 callPackage ./. (args // {
   version = "3.3.5";
-  hash = "sha256-ynLrJvbbK++nfkj/lm9xvNPLRLM72Lu4ELZebQEcHlw=";
+  hash = "sha256-RLHx8PyfbfIDr6X6ky5/w0XsGMFd+v5PgmQHvYOaf+k=";
 })

pkgs/servers/sql/mariadb/connector-c/default.nix

···
-{ lib, stdenv, fetchurl, cmake
+{ lib, stdenv, fetchFromGitHub, cmake
 , curl, openssl, zlib, zstd
 , libiconv
 , version, hash, ...
···
   pname = "mariadb-connector-c";
   inherit version;
 
-  src = fetchurl {
-    url = "https://downloads.mariadb.com/Connectors/c/connector-c-${version}/mariadb-connector-c-${version}-src.tar.gz";
+  src = fetchFromGitHub {
+    owner = "mariadb-corporation";
+    repo = "mariadb-connector-c";
+    rev = "v${version}";
     inherit hash;
   };