chore(deps): bump apollo-server-core from 2.21.1 to 2.26.2

Bumps [apollo-server-core](https://github.com/apollographql/apollo-server/tree/HEAD/packages/apollo-server-core) from 2.21.1 to 2.26.2.
- [Release notes](https://github.com/apollographql/apollo-server/releases)
- [Commits](https://github.com/apollographql/apollo-server/commits/apollo-server-core@2.26.2/packages/apollo-server-core)

---
updated-dependencies:
- dependency-name: apollo-server-core
  dependency-type: indirect
...

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