feat(oracle): NVL2 function

[nxtpge]

This pull request allows to use the Oracle NVL2 function.

Also, the missing lint command described in the README.md was added in the composer.json.

It is based on the GitHub Actions workflows which led me to the ones defined in the Doctrine repository (PHP_CodeSniffer, PHPStan).

By the way, PHPStan found the following errors:

 ------ --------------------------------------------------------------------------------------------
  Line   tests/Query/DbTestCase.php
 ------ --------------------------------------------------------------------------------------------
  26     Call to an undefined static method Doctrine\ORM\ORMSetup::createDefaultAnnotationDriver().
         🪪  staticMethod.notFound
 ------ --------------------------------------------------------------------------------------------

 ------ --------------------------------------------------------------------------------------------
  Line   tests/Types/CarbonDateTest.php
 ------ --------------------------------------------------------------------------------------------
  54     Call to an undefined static method Doctrine\ORM\ORMSetup::createDefaultAnnotationDriver().
         🪪  staticMethod.notFound
  248    Call to an undefined method Doctrine\DBAL\Types\Type::requiresSQLCommentHint().
         🪪  method.notFound
 ------ --------------------------------------------------------------------------------------------

 ------ --------------------------------------------------------------------------------------------
  Line   tests/Types/ZendDateTest.php
 ------ --------------------------------------------------------------------------------------------
  41     Call to an undefined static method Doctrine\ORM\ORMSetup::createDefaultAnnotationDriver().
         🪪  staticMethod.notFound
  118    Call to an undefined method Doctrine\DBAL\Types\Type::requiresSQLCommentHint().
         🪪  method.notFound
 ------ --------------------------------------------------------------------------------------------

[nxtpge]

Maybe it would be a good time to remove support for PHP 7.2 and 8.0 as they are not maintained anymore.

Is that worth considering or do I miss something due to my lack of experience in the open source @beberlei?

[nxtpge]

Hello @derrabus, do you know when are released new major and/or minor versions for this repository?

By looking at the dates of the previous ones, I did not find defined periods.

It will help me to understand when pull requests are merged.

Thank you for your time!