Fix deprecation warning on register_test/4

[sabiwara]

On Elixir's main branch, ExUnit.Properties emits deprecation warnings on ExUnit.Case.register_test/4:

Since StreamData supports Elixir ~> 1.11 and register_test/6 is since: "1.10.0", we can fix it by replacingregister_test/4 by its implementation.

[coveralls]

Pull Request Test Coverage Report for Build bad0863495c0c76c98a2d6158740bf5590330455-PR-192

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 4 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-1.0%) to 93.639%

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Files with Coverage Reduction	New Missed Lines	%
lib/stream_data.ex	4	93.44%

Totals
Change from base Build 83832e2259457bb36c4a2f0a321f4b83258f82e4:	-1.0%
Covered Lines:	368
Relevant Lines:	393

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💛 - Coveralls

[whatyouhide]

Oh sweet good catch @sabiwara! Thanks 💟