Prevent mutation of excludes/includes

[AlexECX]

Change Summary

#1286 mutates the includes/excludes dictionary inside ValueItems, which makes them unusable after use. This PR aims to make includes/excludes arguments immutable.

Related issue number

Related to #959 (comment)

Checklist

• Unit tests for the changes exist
• Tests pass on CI and coverage remains at 100%
• Documentation reflects the changes where applicable
• changes/<pull request or issue id>-<github username>.md file added describing change
  (see changes/README.md for details)

[codecov]

Codecov Report

Merging #1404 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #1404   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           21        21           
  Lines         3736      3740    +4     
  Branches       739       741    +2     
=========================================
+ Hits          3736      3740    +4     

Impacted Files	Coverage Δ
pydantic/typing.py	100.00% <ø> (ø)
pydantic/utils.py	100.00% <100.00%> (ø)
pydantic/types.py	100.00% <0.00%> (ø)

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[AlexECX]

curl: (7) Failed to connect to codecov.io port 443: Connection timed out is that normal?

Edit: Oh well, pushing again fixed the problem.

[samuelcolvin]

good catch, thanks so much for the fix.