Add label as optional arg to @override directive

[Samjin]

Support federation v2.7. Here's directive details
Support progressive @override directive.

These directives will require specific federation versions to generate schema.

1. @authenticate directive is generated from 2.5+
2. @requiresScopes directive is generated from 2.5+
3. @policy directive is generated from 2.6+
4. @composeDirective directive is generated from 2.1+
5. @interfaceObject directive is generated from 2.6+
6. @override directive with 2nd argument of label from 2.7

[dariuszkuc]

Currently this lib allows you specify you own custom @link federation spec import -> this change does not account for this and will update directive definitions even if folks specifically target older versions of federation

[Samjin]

Currently this lib allows you specify you own custom @link federation spec import -> this change does not account for this and will update directive definitions even if folks specifically target older versions of federation

Had a brief discussion, the plan is to check if progressive override label would work with older fed version from composition. if not, we'll have to check fed version per directives to make sure they are correctly generated.

[Samjin]

Somehow fed 2.7.5 with Router 1.47.0 failed,
but 2.7.2 with v1.45.1 worked for composition check.
https://www.apollographql.com/docs/graphos/routing/federation-version-support

[Samjin]

Somehow fed 2.7.5 with Router 1.47.0 failed, but 2.7.2 with v1.45.1 worked for composition check. https://www.apollographql.com/docs/graphos/routing/federation-version-support

Confirmed with Apollo it is a Rover bug and fixed with federation =2.7.8