fix(ci): pin py-cpuinfo to 8.0.0 (#4375) (#4378)

## Description
Our profiler and benchmark test suites currently use pytest-benchmark, which internally relies on a plugin import to `py-cpuinfo`, which has released a major version 9.x dropping support for Python <= 3.6. This has broken our profiler and benchmark test suites, so I've pinned those test suites to use `py-cpuinfo==8.0.0` which was the latest released version which still supports Python<=3.6.

## Checklist
- [ ] Add additional sections for `feat` and `fix` pull requests.
- [ ] [Library documentation](https://github.com/DataDog/dd-trace-py/tree/1.x/docs) and/or [Datadog's documentation site](https://github.com/DataDog/documentation/) is updated. Link to doc PR in description.

## Motivation

## Design

## Testing strategy

## Relevant issue(s)

## Testing strategy

## Reviewer Checklist
- [ ] Title is accurate.
- [ ] Description motivates each change.
- [ ] No unnecessary changes were introduced in this PR.
- [ ] Avoid breaking [API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces) changes unless absolutely necessary.
- [ ] Tests provided or description of manual testing performed is included in the code or PR.
- [ ] Release note has been added for fixes and features, or else `changelog/no-changelog` label added.
- [ ] All relevant GitHub issues are correctly linked.
- [ ] Backports are identified and tagged with Mergifyio.

(cherry picked from commit f8ebe5f)

Co-authored-by: Yun Kim <[email protected]>

riotfile.py

@@ -217,7 +217,10 @@ def select_pys(min_version=MIN_PYTHON_VERSION, max_version=MAX_PYTHON_VERSION):
         Venv(
             pys=select_pys(),
             pkgs={
+                # pytest-benchmark depends on cpuinfo which dropped support for Python<=3.6 in 9.0
+                # See https://github.com/workhorsy/py-cpuinfo/issues/177
                 "pytest-benchmark": latest,
+                "py-cpuinfo": "~=8.0.0",
                 "msgpack": latest,
                 # TODO: remove py dependency once https://github.com/ionelmc/pytest-benchmark/pull/227 is released
                 "py": latest,

tox.ini

@@ -112,6 +112,9 @@ deps =
     hypothesis
 # used to test our custom msgpack encoder
     profile: pytest-benchmark
+    # pytest-benchmark depends on cpuinfo which dropped support for Python<=3.6 in 9.0
+    # See https://github.com/workhorsy/py-cpuinfo/issues/177
+    profile: py-cpuinfo==8.0.0
     # TODO: remove py dependency once https://github.com/ionelmc/pytest-benchmark/pull/227 is released
     profile: py
     py{35,36,37,38,39,310}-profile: pytest-asyncio