Update apollo-link-rest.md - Add graphql-anywhere to install list

[pfcodes]

Added graphql-anywhere to the install string. apollo-link-rest does not work without this library installed.

Somewhat related:
apollographql/apollo-link-rest#295

[apollo-cla]

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[jpvajda]

Here is the error I am getting when trying to follow the instructions from this docs page

npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR! 
npm ERR! While resolving: [email protected]
npm ERR! Found: [email protected]
npm ERR! node_modules/graphql
npm ERR!   graphql@"^16.6.0" from the root project
npm ERR!   peer graphql@">=0.11" from [email protected]
npm ERR!   node_modules/apollo-link-rest
npm ERR!     apollo-link-rest@"*" from the root project
npm ERR!   3 more (@apollo/client, graphql-ws, subscriptions-transport-ws)
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peer graphql@"^0.11.0 || ^0.12.0 || ^0.13.0 || ^14.0.0 || ^15.0.0" from [email protected]
npm ERR! node_modules/graphql-anywhere
npm ERR!   peer graphql-anywhere@">=4" from [email protected]
npm ERR!   node_modules/apollo-link-rest
npm ERR!     apollo-link-rest@"*" from the root project
npm ERR! 
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR! 
npm ERR! See /Users/jvajda/.npm/eresolve-report.txt for a full report.

npm ERR! A complete log of this run can be found in:

Given the state of the graphql anywhere project, I'm not sure we want to reference this package in the documentation, however it brings up a question of what should we do here. I'll discuss with the team @pfcodes Thanks for bring this to our attention.