requirements: update grpcio requirement from <1.81.0,>=1.60.0 to >=1.60.0,<1.82.0

[dependabot]

Updates the requirements on grpcio to permit the latest version.

Release notes

Sourced from grpcio's releases.

Release v1.81.0

This is release 1.81.0 (graphic) of gRPC Core.

For gRPC documentation, see grpc.io. For previous releases, see Releases.

This release contains refinements, improvements, and bug fixes, with highlights listed below.

Core

• [EventEngine] Fix a potential use-after-free error on Windows. (#42078)
• [ssl] Server side handshaker factory stores a map of key signers. (#42002)
• [Core] Fix completion queue shutdown race on weak memory models (ARM). (#41510)
• [EventEngine] Fix a Windows race that causes an assertion error. (#41563)
• [grpc_error] enable error_flatten experiment in OSS. (#41471)
• [Python] Trim Python2 backward compatiblity syntax - removed (object) inheritance. (#41708)

Objective-C

• [ObjC] Add receiveNextMessage to GRPCUnaryProtoCall. (#42260)

Python

• [Python] Add typing_extensions dep to aio Bazel target. (#42001)
• [Python] [Pyright] Part 1 - Pyright for src/python/grpcio/grpc/aio/_base_server.py. (#42240)
• [Python] Drop 3.9. (#42145)
• [Python] grpc-status: Relax protobuf dependency upper bound to allow 7.x. (#41948)
• [Python] [Typeguard] Part 5 - Add Typeguard SYNC Stack in tests. (#40278)
• [Python] Remove GIL from ReceiveMessageOperation.un_c method. (#41812)
• [Python] Support observability in AsyncIO stack. (#41573)

Ruby

• [Ruby] Drop support for EOL Ruby 3.1 and clean up. (#41435)
• [Ruby] Composed CallCredentials keep a reference to their source. (#41782)

Commits

• 8bdf11e [Release] Bump version to 1.81.0 (on v1.81.x branch) (#42432)
• 0029e06 Move all gRPC Session classes to the experimental namespace (#42462)
• 1f18268 [CI] Fix Asan thread_stress_test error by reducing thread count (#42424) (#42...
• ee3fed7 Backport MacOS fix cl/917004588 to v1.81.x (#42441)
• 6244f3b [Release] Bump version to 1.81.0-pre1 (on v1.81.x branch) (#42378)
• 1108777 [Release] Bump core version to 54.0.0 for upcoming release (#42321)
• 74940e8 [fix] Add back the do-while loop that handles the TSI_RESULT correctly.
• 5c6185c [CHTTP2] Assert
• 51bc437 Automated rollback of commit aab1eab78f9fcb3fc6e0aa9c8d7a59de280dbe3f.
• 03a2dc7 [Cleanup] Reduce log noise in latent see.
• Additional commits viewable in compare view

[github-actions]

This PR causes the following changes to the html docs (ubuntu-latest-3.11):

No differences!

...

See CI logs for the full diff.

[jvesely]

@dependabot rebase

[github-actions]

This PR causes the following changes to the html docs (ubuntu-latest-3.11):

No differences!

...

See CI logs for the full diff.

[jvesely]

@dependabot rebase

[dependabot]

Looks like grpcio is no longer updatable, so this is no longer needed.