Update dependency phpstan/phpstan to v1.5.3

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
phpstan/phpstan	require-dev	patch	1.5.2 -> 1.5.3

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Release Notes

phpstan/phpstan

v1.5.3

Compare Source

Improvements 🔧

• Update phpdoc-parser with multi-line union/intersection/conditional types support (phpstan/phpstan-src@6fa7c90), https://github.com/phpstan/phpdoc-parser/pull/114, thanks @​rvanvelzen!

Bugfixes 🐛

• Mark Memcached::HAVE_* constants as dynamic (#​1142), #​6263, thanks @​VasekPurchart!
• Improve return types for array_fill_keys and array_combine (#​1139), thanks @​canvural!
• Guard Equal (==) expression specification with empty array on both sides (#​1143), #​6940, thanks @​herndlm!
• Fix huge union types result from "+"-array-merge operation (#​1141), #​6936, thanks @​staabm!
• Improve return type of array_fill_keys for not constant arrays (#​1145), thanks @​canvural!
• Handle false return in substr() with PHP < 8 (#​1144), #​6939, thanks @​herndlm!
• array_merge lost non-empty-string keys type (#​1135), #​6927, #​5846, #​2567, thanks @​staabm!

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