Fix protobuf resolution knot for pip 25.1

[notatallshaw]

Related to #51702.

There is a resolution "knot" involving protobuf when pip 25.1 attempts to resolve dependencies during CI. Many Google dependencies require protobuf, but grpcio-status and opentelemetry-proto often have conflicting version requirements, for example:

• grpcio-status 1.73.0 requires protobuf<7.0.0,>=6.30.0
• opentelemetry-proto 1.27.0 requires protobuf<5.0,>=3.19

Because so many packages depend on protobuf, pip's heuristics struggle to correctly identify which packages to backtrack on, leading to resolution too deep errors.

This change introduces a workaround by adding opentelemetry-proto with an upper bound to the dependency list. This signals to pip that the package should be resolved early, while the use of a very high upper bound ensures that it doesn't meaningfully restrict user environments. I considered using a requirement like opentelemetry-proto<2!0, but decided against it, as it felt too magical and might break tools that are not fully PEP 440 compliant.

[potiuk]

Whoa!

[potiuk]

Let's see if our canary build likes it :)

[potiuk]

Thanks @notatallshaw -> it helped of course though it's still a bit non-obvious how :). Looking forward to 25.2 !

[amoghrajesh]

Thats really nice! Thanks

[notatallshaw]

it helped of course though it's still a bit non-obvious how

Yeah, unfortunately it only becomes obvious when you look into the internal state of resolvelib.