docs: Adds SPI badges

Author: NeedleInAJayStack

README.md

@@ -1,5 +1,8 @@
 # GraphQL Generator for Swift
 
+[![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2FGraphQLSwift%2Fgraphql-generator%2Fbadge%3Ftype%3Dplatforms)](https://swiftpackageindex.com/GraphQLSwift/graphql-generator)
+[![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2FGraphQLSwift%2Fgraphql-generator%2Fbadge%3Ftype%3Dswift-versions)](https://swiftpackageindex.com/GraphQLSwift/graphql-generator)
+
 This is a Swift package plugin that generates server-side GraphQL API code from GraphQL schema files, inspired by [GraphQL Tools' makeExecutableSchema](https://the-guild.dev/graphql/tools/docs/generate-schema) and [Swift's OpenAPI Generator](https://github.com/apple/swift-openapi-generator).
 
 ## Features