Promote beta features

[leonard84]

Promote @Beta features that existed before 2.4

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.13%. Comparing base (c103586) to head (3fe9656).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #2278   +/-   ##
=========================================
  Coverage     82.13%   82.13%           
+ Complexity     4794     4793    -1     
=========================================
  Files           469      469           
  Lines         14958    14958           
  Branches       1888     1888           
=========================================
  Hits          12286    12286           
  Misses         1984     1984           
  Partials        688      688           

Files with missing lines	Coverage Δ
...rg/spockframework/mock/CallRealMethodResponse.java	100.00% <ø> (ø)
...va/org/spockframework/mock/MockImplementation.java	100.00% <ø> (ø)
.../main/java/org/spockframework/mock/MockNature.java	100.00% <ø> (ø)
...rc/main/java/org/spockframework/mock/MockUtil.java	100.00% <ø> (ø)
...va/org/spockframework/mock/ZeroOrNullResponse.java	100.00% <ø> (ø)
...spockframework/mock/runtime/MockConfiguration.java	100.00% <ø> (ø)
...ckframework/mock/runtime/MockCreationSettings.java	100.00% <ø> (ø)
.../spockframework/runtime/extension/IDataDriver.java	100.00% <ø> (ø)
...kframework/runtime/extension/IIterationRunner.java	0.00% <ø> (ø)
...tension/builtin/PendingFeatureSuccessfulError.java	100.00% <ø> (ø)
... and 15 more

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[AndreasTu]

LGTM.

Thanks for the cleanup.

[szpak]

It would be worth to mention mass out-of-beta change in the release notes (in general). I'm not sure, if it has to be with all the features mentioned by name there.