Bumping graphql-tag, ignoring deprecation warnings

[jnwng]

graphql-tag has deprecated the export of the printer export (which we use for various AST-related tasks here in apollo-client). when graphql-tag@v2 comes out, we can switch to using the printer / parser from the graphql package, but for now we know about the deprecation warning and can safely ignore it.

addresses graphql-tag#54

TODO:

• Make sure all of the significant new logic is covered by tests
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass
• Update CHANGELOG.md with your change
• Add your name and email to the AUTHORS file (optional)
• If this was a change that affects the external API, update the docs and post a link to the PR in the discussion