fix(apollo): Update resolveReference location

[trevor-scheer]

The location of resolveReference was updated in the @apollo/subgraph library to live on a type's extensions object rather than directly on the object itself. The extensions are treated as public API w.r.t. graphql-js.

Reference:
apollographql/federation#1746
apollographql/federation#1747

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• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
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PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
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Issue Number: #2228

Does this PR introduce a breaking change?

• Yes
• No

[trevor-scheer]

If there were tests in place for this previously, they would have failed when updating devDependencies.@apollo/subgraph to 0.4.2 in #2155. Would someone mind helping me add tests for this? This would let me confirm backcompat and that this change does indeed fix the issue that was originally introduced.

[kamilmysliwiec]

LGTM

[trevor-scheer]

@kamilmysliwiec I still think this needs tests...