Bump google.golang.org/grpc from 1.59.0 to 1.60.1

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.59.0 to 1.60.1.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.59.0...v1.60.1)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/google.golang.org/grpc/internal/envconfig/envconfig.go

@@ -36,9 +36,6 @@ var (
 	// "GRPC_RING_HASH_CAP".  This does not override the default bounds
 	// checking which NACKs configs specifying ring sizes > 8*1024*1024 (~8M).
 	RingHashCap = uint64FromEnv("GRPC_RING_HASH_CAP", 4096, 1, 8*1024*1024)
-	// PickFirstLBConfig is set if we should support configuration of the
-	// pick_first LB policy.
-	PickFirstLBConfig = boolFromEnv("GRPC_EXPERIMENTAL_PICKFIRST_LB_CONFIG", true)
 	// LeastRequestLB is set if we should support the least_request_experimental
 	// LB policy, which can be enabled by setting the environment variable
 	// "GRPC_EXPERIMENTAL_ENABLE_LEAST_REQUEST" to "true".