Drop support for legacy PHP versions about phpclickhouse

[isublimity]

I do not see any problems in that the library supports the old version, and I think this does not affect its quality and security.
If you are using the latest version of PHP in the project - support for the old version does not bother you.
And i repeat - I need support for this version

[isublimity]

31 Dec 2018 - i delete support 5.6)

[simPod]

Security not yet, but quality it does. Eg.

• you cannot run higher levels of PHPStan and
• cannot use more strict type definitions.

The result is that the types are ofter incorrectly documented and I'd bet there are many bugs that we haven't found yet because of those two.

31. 12. it is then, note taken.

[simPod]

Btw, wasn't meant this to be hostile, I know you mentioned it earlier there's a project of yours running on lower PHP version. That's why I created issue only and not PR.

[isublimity]

i'm ask community drop 5.6

[isublimity]

I drop 5.6

[simPod]

👏

I suggest to make it ^7.1 straight as 7.0's EOL is in 6 months anyway. 7.1 brings cool features like nullables or void types and compared to 7.0 is not very different