Fix multiple versions of msgpack being used

[fxamacker]

Updates #7242

Currently, import statements are using different versions of msgpack:

• github.com/vmihailenco/msgpack
• github.com/vmihailenco/msgpack/v4

They cause go.mod to import different versions of msgpack:

• msgpack (v4.0.4)
• msgpack/v4 (v4.3.12)

Also, the msgpack version used by non-test code and test code sometimes doesn't match.

This PR replaces import statements using "msgpack" with import statements using "msgpack/v4". This change specifies a specific major version number and prevents different versions of msgpack being used by mistake.

I found this while getting familiar with storage code related to BadgerDB and Pebble (not looking for bugs).

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41.11%. Comparing base (926dbc0) to head (b51fba2).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7399   +/-   ##
=======================================
  Coverage   41.10%   41.11%           
=======================================
  Files        2207     2207           
  Lines      193498   193498           
=======================================
+ Hits        79544    79550    +6     
+ Misses     107325   107321    -4     
+ Partials     6629     6627    -2     

Flag	Coverage Δ
unittests	41.11% <ø> (+<0.01%)	⬆️

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[zhangchiqing]

Thanks Faye

[zhangchiqing]

Could we double check the existing version and v4 are encoding into the same bytes data? Do we need some test case to verify?

[fxamacker]

Could we double check the existing version and v4 are encoding into the same bytes data? Do we need some test case to verify?

Good question.

I don't see tagged releases (on GitHub with release notes) for msgpack and their CHANGELOG.md doesn't show changes within v4 (no details about v4.x -> 4.y versions).

However, there seems to be a lot of bugfixes and performance/memory improvements between v4.0.4 and v4.3.12 based on git comparison.

Do we need some test case to verify?

This might be tricky (for someone unfamiliar with the code and the data used) because some code is calling Marshal on interface type, e.g. flow.Entity, or any type. Maybe people more familiar with the code and data can add some test cases.

BTW, I noticed in some cases non-test code used different msgpack version than the test code. So this PR made msgpack versions used by non-tests and tests consistent too.