remove graphql codegen cli alias names

[n1ru4l]

trafficstars

Right now we have 3 ways of running the CLI:

    "gql-gen": "dist/cjs/bin.js",
    "graphql-codegen": "dist/cjs/bin.js",
    "graphql-code-generator": "dist/cjs/bin.js",

Most commonly used one is graphql-codegen. We can remove the other ones in the next major version.

[saihaj]

we might want to find a way how to get access to graphql-codegen name since it doesn't work properly with npx see https://github.com/dotansimha/graphql-code-generator/issues/8074#issuecomment-1180893362