Using npm 7 peer dependencies with Gatsby Cloud

If you are using npm 7, you may encounter conflicting peer dependencies that cause a build failure.  To force through this error message and use the peer dependency behavior of npm 3 - 6, add the environment variable NPM_CONFIG_LEGACY_PEER_DEPS=true will force the legacy behavior.  Be aware that, per the npm docs, use of legacy-peer-deps is not recommended, as it will not enforce the peerDependencies contract that meta-dependencies may rely on.