Test enhancement for fix PSR-4 autoloading

[peter279k]

Changed log

• Remove classmap-authoritative to avoid deprecated PSR-4 autoloading warning message.
• Modify the PHP file name and let this file name be same as class name. It can be loading class correctly during composer autoloading generating.

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This change is 

[peter279k]

Revert the PSR-2 coding style and it can avoid PSR-12 coding style checking to cause the Travis CI build failed.

[hopeseekr]

There are many things about PSR-12 that I like, in fact most things. In fact, the only thing I disagree with is that they no longer allow <?php declare(strict_types=1);, which I strongly feel is the bestest way to declare this.

Here is the corporate workaround:
PHPExpertsInc/SimpleDTO@1faa8a4

I'm pretty sure all of our projects modded after April 8th 2020 are failing this test.

[peter279k]

Is it possible to consider using phpcs.xml file to ignore declare(strict_types=1); checking?

[peter279k]

@hopeseekr, after searching some solutions about ignoring declare strict type checking, here is the proper solution:

The phpcs.xml file is as follows:

<?xml version="1.0"?>
<ruleset name="Custom Standard" namespace="MyProject\CS\Standard">
  <rule ref="PSR12">
    <exclude name="PSR12.Files.FileHeader" />
    <exclude name="PSR12.Files.OpenTag" />
  </rule>
</ruleset>

[peter279k]

To fix following error during PHPStan static code analyzing, using this phpstan.neon file to ignore checkMissingIterableValueType setting.

[hopeseekr]

https://github.com/phpexpertsinc/SimpleDTO/blob/master/phpstan.neon

[peter279k]

Add php-7.4 version test during Travis CI build.

[hopeseekr]

Thank you very much for this PR.

I am merging it next time I see it if I don't fix the issues myself.

Thank you for encouraging me.