Support logical types in Schema export

Thanks @smalot

PHP 7.4 support & deprecations release

This release adds PHP 7.4 to the travis test targets and fixes some deprecation notes in #6.

Thanks @offdev

Support for logical types and CI integration

3.0.0

Ported changes from wikimedia (incl. logical types) and CI integratio…

Forked from rg/avro-php and fixed two critical issues

• Fix for Uninitialized string offset exception. The error was mainfesting when serializing avro schemas with array types.
• Fixes the case where fread(1) returns an empty string. Fix added from rdblue/avro-php.