Add openapi-generate-html

Signed-off-by: Oliver Davies <oliver@oliverdavies.uk>

openapi/flake.nix

@@ -9,6 +9,10 @@
     in
     {
       packages.${system} = {
+        openapi-generate-html = import ./openapi-generate-html.nix {
+          inherit (pkgs) buildNpmPackage fetchFromGitHub;
+        };
+
         openapi-mock = import ./openapi-mock.nix {
           inherit (pkgs) buildGoModule fetchFromGitHub;
         };
@@ -19,6 +23,7 @@
           openapi-generator-cli
           openapi-tui
 
+          self.packages.${system}.openapi-generate-html
           self.packages.${system}.openapi-mock
         ];
       };