chore(deps): update grpcio-tools requirement from <1.81,>=1.60 to >=1.60,<1.82

[dependabot]

Updates the requirements on grpcio-tools to permit the latest version.

Release notes

Sourced from grpcio-tools's releases.

Release v1.81.1

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)

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)
• [Python] Trim Python2 backward compatiblity syntax - removed (object) inheritance. (#41708)

Ruby

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

Commits

• e84a8a2 [Release] Bump version to 1.81.1 (on v1.81.x branch) (#42584)
• 8bdf11e [Release] Bump version to 1.81.0 (on v1.81.x branch) (#42432)
• 6244f3b [Release] Bump version to 1.81.0-pre1 (on v1.81.x branch) (#42378)
• 820f933 [Python] Drop 3.9 (#42145)
• 451521c [Core CI] Make windows python distrib tests use ccache. (#42171)
• cb09882 [Build] Upgrade protobuf to 33.5 (#41976)
• a2bf3f1 [Release] Bump version to 1.81.0-dev (on master branch) (#41843)
• 1299baa [Python] Add language features to exported proto files (#41501)
• 522dbbb [Release] Bump version to 1.79.0-dev (on master branch) (#41291)
• 0a6901d [python xDS protos] move to a shallower directory (#41261)
• Additional commits viewable in compare view

[jjviscomi]

Holding this for now rather than declining it. The <1.81 cap on grpcio-tools is deliberate, and the precondition for lifting it (documented in the pyproject.toml comment next to the pin) is not yet met.

Why:

• grpcio-tools declares Requires-Dist: grpcio>=<its own version>, so a grpcio-tools newer than the installed grpcio is a pip-flagged incompatibility, and the generated stubs expect a matching grpcio runtime.
• Five Python example CI jobs install bqemulator editable (pip install -e ".[dev,all]") and then their hash-pinned requirements.txt. Four of them (pytest-integration, dbt-local, airflow-dag-test, pyspark-bigquery) pin grpcio==1.80.0; only export-to-gcs is on grpcio==1.81.0.
• Lifting the cap to <1.82 lets the editable install pull grpcio-tools==1.81, then requirements.txt pins grpcio==1.80.0 back down while leaving grpcio-tools at 1.81 (it is not in the lock). That is grpcio-tools 1.81 newer than grpcio 1.80, the exact skew the cap prevents.
• This PR only touches pyproject.toml, which is not in examples.yml's path filter, so those example jobs do not run here. The breakage would be latent (surfacing on the next docs/examples/** PR or the nightly sweep) rather than caught at merge.

There is no CVE forcing this bump, so we will hold until the remaining example grpcio client locks move to >=1.81 (the comment's stated precondition), then lift grpcio-tools and grpcio-health-checking together and update the comment. Leaving this open so it can be picked up at that point.