Update dependency phpstan/phpstan to v1.4.4

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
phpstan/phpstan	require-dev	patch	1.4.3 -> 1.4.4

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Release Notes

phpstan/phpstan

v1.4.4

Compare Source

Improvements 🔧

• Return type extension for array_column() (#​948), thanks @​jlherren!
• Generic stub for DatePeriod + constructor dynamic return type extension (#​958), #​5953, thanks @​Alban-io!
• Resolve remaining predefined constants (#​693), thanks @​herndlm!

Bugfixes 🐛

• Support all array_filter() flags for narrowing down types (#​941), thanks @​herndlm!
• Fix error The supplied range exceeds the maximum array size (#​934), #​6375, thanks @​voku!
• Nullable union template type bound is actually supported (phpstan/phpstan-src@1d8b2eb), #​4656, #​5305, #​3384
• Fix reporting nonexistent offset in isset() (phpstan/phpstan-src@f05e8eb), #​4926
• Fix interaction between template type and intersection type (#​955), #​6210, thanks @​arnaud-lb!
• Fix tests on 32-bit (#​957), thanks @​herndlm!
• Fix resolving type of isset(), empty() and null coalesce operator (??) (phpstan/phpstan-src@3b17acc), #​4592, #​4903, #​2420, #​2718, #​3126, #​4586, #​4887

Function signature fixes 🤖

• Narrow down the return type of the Throwable::getTrace() method (#​914), thanks @​ste93cry!
• Fix DOMDocument::saveXML signature (#​956), thanks @​kissifrot!

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