Matt Fong

fix(docs): update readme for adding Apollo Federation tracing

2

I made a request to my rails server running locally and set the header `apollo-federation-include-trace` ```ruby headers => {"X-Frame-Options"=>"SAMEORIGIN", "X-XSS-Protection"=>"1; mode=block", "X-Content-Type-Options"=>"nosniff", "X-Download-Options"=>"noopen", "X-Permitted-Cross-Domain-Policies"=>"none", "Referrer-Policy"=>"strict-origin-when-cross-origin"} headers['apollo-federation-include-trace'] => nil request.headers['apollo-federation-include-trace'] =>...