Update dependency graham-campbell/manager to v4

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
graham-campbell/manager	require	major	^3.0 -> ^4.0.0

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Release Notes

GrahamCampbell/Laravel-Manager

v4.3.0

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• Added Laravel 6 support

v4.2.2

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• Avoid calling deprecated code

v4.2.1

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• Fixes for PHPUnit 8

v4.2.0

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• Added Laravel 5.8 support

v4.1.0

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• Added Laravel 5.7 support

v4.0.0

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• Support PHP 7.1 or 7.2
• Support Laravel 5.5 or 5.6
• Bind extension resolvers to the manager
• Updated phpdoc to reflect connections being objects

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