Update flake.nix for v0.23.0 (#191)

Updates flake.nix version to 0.23.0 for the v0.23.0 release.

Author: wesm

flake.nix

@@ -15,7 +15,7 @@
         packages = {
           default = pkgs.buildGoModule {
             pname = "roborev";
-            version = "0.22.1";
+            version = "0.23.0";
 
             src = ./.;