CI: Test against multiple graphql versions

[robhogan]

Currently tests are run against the latest version of graphql matching the semver expression in devDependencies.

This PR aims to ensure that as we support new versions of graphql we don't introduce regressions for older ones, and we can have confidence in the peerDependencies range.

Type checking is not enforced when using the matrix to specify a version of graphql to test against, because:

• It makes the CI config simpler not to have to work out whether @types/graphql is necessary and what version it should be at for any given graphql version.
• Older and imperfect type definitions mean that CI would fail on type check even though the built package would work perfectly well - eg old @types/graphql definitions did not allow field extensions for some time after graphql implemented them.

Type checking is enforced in the test-and-build-with-typecheck job, which respects yarn.lock and runs tsc