Strawberry GraphQL: Default GraphiQL may expose HTTP headers in URLs

Strawberry GraphQL is a library for creating GraphQL APIs. In versions 0.288.4 through 0.315.3, Strawberry's bundled GraphiQL template wrote values from the GraphiQL headers editor into the browser URL query string. If a user entered a sensitive header, such as `Authorization: Bearer <token>`, the value could become visible in browser history, copied links, and server/proxy/CDN access logs after a page reload or shared request. Version 0.315.4 patches the issue.