Pin the version of cloudpickle to 2.1.x

[tvalentyn]

Tighten the bound of cloudpickle, since cloudpickle will now be used as default in Python-on-Java xlang scenario for reasons outlined in #23119

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[tvalentyn]

R: @robertwb @ryanthompson591

[codecov]

Codecov Report

Merging #23120 (d978d86) into master (31561e2) will decrease coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #23120      +/-   ##
==========================================
- Coverage   73.71%   73.62%   -0.09%     
==========================================
  Files         714      716       +2     
  Lines       95240    95299      +59     
==========================================
- Hits        70203    70164      -39     
- Misses      23740    23838      +98     
  Partials     1297     1297              

Flag	Coverage Δ
python	83.40% <ø> (-0.14%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ks/python/apache_beam/runners/worker/statecache.py	89.69% <0.00%> (-6.47%)	⬇️
...dks/python/apache_beam/metrics/monitoring_infos.py	92.50% <0.00%> (-4.50%)	⬇️
...python/apache_beam/runners/worker/worker_status.py	76.00% <0.00%> (-3.72%)	⬇️
sdks/python/apache_beam/internal/pickler.py	92.00% <0.00%> (-3.46%)	⬇️
sdks/python/apache_beam/utils/interactive_utils.py	95.12% <0.00%> (-2.44%)	⬇️
...ks/python/apache_beam/runners/worker/data_plane.py	87.57% <0.00%> (-1.70%)	⬇️
.../python/apache_beam/transforms/periodicsequence.py	98.38% <0.00%> (-1.62%)	⬇️
...eam/runners/portability/fn_api_runner/execution.py	92.44% <0.00%> (-0.65%)	⬇️
sdks/python/apache_beam/runners/direct/executor.py	96.46% <0.00%> (-0.55%)	⬇️
...eam/runners/interactive/interactive_environment.py	91.71% <0.00%> (-0.31%)	⬇️
... and 15 more

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[github-actions]

Stopping reviewer notifications for this pull request: review requested by someone other than the bot, ceding control

[ryanthompson591]

I'm more worried that a tight cloudpickle dependency will cause more conflicts with other libraries than dill.

I suppose we can roll this back if it causes too many problems, or better yet, vendor all our pickle libraries.