mbedtls_2: 2.28.7 -> 2.28.8

Changelog: https://github.com/Mbed-TLS/mbedtls/releases/tag/v2.28.8
Fixes CVE-2024-28960

pkgs/development/libraries/mbedtls/2.nix

@@ -1,6 +1,6 @@
 { callPackage }:
 
 callPackage ./generic.nix {
-  version = "2.28.7";
-  hash = "sha256-JI0Frbz4HkPqrLQNrSIj1ikN8201h4kd1wTwyPotERw=";
+  version = "2.28.8";
+  hash = "sha256-A1DYZrvJ8SRujroVwqPfcTOSgLnT5xRat/RVdq2fL/o=";
 }

pkgs/development/libraries/mbedtls/generic.nix

@@ -21,6 +21,8 @@ stdenv.mkDerivation rec {
     repo = "mbedtls";
     rev = "${pname}-${version}";
     inherit hash;
+    # mbedtls >= 3.6.0 uses git submodules
+    fetchSubmodules = true;
   };
 
   nativeBuildInputs = [ cmake ninja perl python3 ];