fix: pin protobuf>=5.29.6,<6.0dev to prevent gencode/runtime version mismatch

[aki1770-del]

Problem

Fixes #54. Installing kuksa-client via pip install kuksa-client fails with:

RuntimeWarning: Detected incompatible Protobuf Gencode/Runtime versions

The root cause: grpcio-tools==1.68.0 requires protobuf>=5.26.1 but does not pin a maximum. pip may resolve to a protobuf version that is incompatible with the .proto-generated _pb2.py files included in the package. In the reported case, protobuf 5.27.3 was installed at build time and 5.29.x at runtime — the version check in _pb2.py fails.

Fix

Add explicit protobuf >= 5.29.6, < 6.0dev constraint to:

• setup.cfg install_requires — ensures the runtime installs a compatible version
• pyproject.toml build-system.requires — ensures the build generates _pb2.py files with the same protobuf version

The <6.0dev upper bound follows the established grpcio/grpcio-tools pattern of excluding the next major (which has breaking generated code changes). The lower bound matches grpcio-tools==1.68.0's resolved protobuf==5.29.6.

No API changes

This is a dependency metadata fix only. No Python source files change.

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AI-assisted — authored with Claude, reviewed by Komada.

[SebastianSchildt]

Possible duplicate of #55 (that also has been lying around for too long....)

[aki1770-del]

You're right — this is effectively a duplicate of #55. @psch0rr's PR is earlier and takes the same approach (protobuf constrained in both pyproject.toml build requires and setup.cfg install_requires, per @erikbosch's suggestion in #54). Deferring to #55 and closing this one. Sorry for the slow reply.

One small point, purely as input for your review of #55: this PR used a range (protobuf>=5.29.6,<6.0dev, following the existing grpcio <6.0dev pattern) instead of the exact ==5.29.6 pin — an exact pin in install_requires can collide with other packages' constraints in a user's environment, while either form fixes #54. If you end up preferring the range, feel free to lift this diff into #55; no attribution needed.