Why `protobuf >= 4.21.2`?

[bluenote10]

Recently the dependency on protobuf has been bumped to >=4.21.2, but apparently without a related code change (at least not in the same commit). I'm wondering why this was necessary?

From what I can see this leads to massive problems with other libraries in the ecosystem. In particular:

• tensorflow 2.9.1 itself has a dependency protobuf<3.20,>=3.9.2
• tensorboard 2.9.1 has a dependency protobuf<3.20,>=3.9.2
• tensorflowjs 3.19.0 has a dependency protobuf==3.20.0
• tflite-support 0.4.1 has a dependency protobuf<4

Due to the note-seq's requirement of protobuf>=4.21.2 it basically becomes unusable in the tensorflow ecosystem. This doesn't seem to make sense, in particular if nothing obvious has changed in the code? Shouldn't it be much more liberal in the protobuf version to avoid this dependency hell?