Add Saleor 3.21+ support (#28)

* Use local 3.21 Saleor schema

* Add tests

Author: maarcingebala

README.md

@@ -10,7 +10,7 @@ Easiest way to try out the Saleor MCP server is by visiting the production insta
 
 https://mcp.saleor.app/
 
-You can connect to the server with Streamable HTTP at `https://mcp.saleor.app/mcp` endpoint. See the Configuration section below for details on required headers. The production instance is configured to connect to Saleor instances hosted on `saleor.cloud` domain and it's compatible with Saleor 3.22.
+You can connect to the server with Streamable HTTP at `https://mcp.saleor.app/mcp` endpoint. See the Configuration section below for details on required headers. The production instance is configured to connect to Saleor instances hosted on `saleor.cloud` domain and it's compatible with Saleor 3.21+.
 
 ## Installation
 

pyproject.toml

@@ -98,7 +98,7 @@ addopts = [
 ]
 
 [tool.ariadne-codegen]
-remote_schema_url = "https://master.staging.saleor.cloud/graphql/"
+schema_path = "./schema.graphql"
 queries_path = "src/saleor_mcp/graphql"
 target_package_name = "saleor_client"
 target_package_path = "src/saleor_mcp"