Fixed ObjectStorage PHPDoc of contentLength and lastModified

[vitalybaev]

This properties have wrong types in PHPDoc

[coveralls]

Pull Request Test Coverage Report for Build 595

• 0 of 0 (NaN%) changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.06%) to 96.057%

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Files with Coverage Reduction	New Missed Lines	%
src/Common/JsonSchema/JsonPatch.php	1	100.0%

Totals
Change from base Build 582:	-0.06%
Covered Lines:	1681
Relevant Lines:	1750

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💛 - Coveralls

[haphan]

thanks @vitalybaev 🚀

[vitalybaev]

@haphan Thanks a lot! Could you ship a new patch release, cause Scrutinizer marks our code as bug due to incompatible types.