Support for PHP and PHPUnit versions discrapency

[czoIg]

In composer.json there's:

"require" : {
	"php" : ">=5.3.2"
}

but there's also:

"require-dev" : {
	...
	"phpunit/phpunit" : "^9.5.13",
	...
}

which produces error in travis:

  Problem 1
    - phpunit/phpunit[9.5.13, ..., 9.5.21] require php >=7.3 -> your php version (5.4.45) does not satisfy that requirement.

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There's also migration issue320Test.php which uses unsupported PHPUnit_Framework_TestCase.