Bump grpcio from 1.55.0 to 1.56.0 in /test/environment/grpc (#462)

Bumps [grpcio](https://github.com/grpc/grpc) from 1.55.0 to 1.56.0.
- [Release notes](https://github.com/grpc/grpc/releases)
- [Changelog](https://github.com/grpc/grpc/blob/master/doc/grpc_release_schedule.md)
- [Commits](grpc/grpc@v1.55.0...v1.56.0)

---
updated-dependencies:
- dependency-name: grpcio
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

test/environment/grpc/requirements.txt

@@ -1,4 +1,4 @@
-grpcio==1.55.0
+grpcio==1.56.0
 grpcio-health-checking==1.55.0
 grpcio-reflection==1.55.0
 grpcio-testing==1.55.0