protobuf3_19: 3.19.5 -> 3.19.6

https://github.com/protocolbuffers/protobuf/releases/tag/v3.19.6

pkgs/development/libraries/protobuf/3.19.nix

···
 { callPackage, ... }:
 
 callPackage ./generic-v3.nix {
-  version = "3.19.5";
-  sha256 = "sha256-C5ZfPXHtUtNjPGS4tbswCwVH1gjd6A64KtIR16DgHzQ=";
+  version = "3.19.6";
+  sha256 = "sha256-+ul9F8tyrwk2p25Dd9ragqwpYzdxdeGjpXhLAwKYWfM=";
 }