[DEPS] Bump version of `guzzlehttp/promises` to also allow v2.0

Bump version of guzzlehttp/promises to also allow v2.0.

PHP 8.2 support

This adds support for PHP 8.2

Bugfix release

#69 Fix encode method with Symfony v6

Thanks @BafS for the contribution!

1.7.1

#56 Fix null terminated string decoding [@alexeevdv ]

PHP 8 support and Schema annotation improvements

Allow referencing previously defined named types (#51)

Once a named type is defined, in order to reuse that same type it is
needed to reference that type by the name (as in the primitive types).

Add support for NamedTypes in both the schema builder and the schema
generator, which is a way of referencing previously defined named types.

Add support for adding extra attributes for records in field's
definition.

PHP 8.0 support & CI overhaul

This release comes with multiple changes regarding the PHP 8 support:

• PHP 7.2 support has been dropped
• Multiple dependencies have been bumped to accomodate for PHP8 support
• Migration of the CI pipeline to GitHub Actions and Code Climate

Fix whitespace en-/decoding in `Protocol`

[FIX] Use `a` instead of `A` binary decoding in `Protocol.php` (#45)

* Use `a` instead of `A` binary decoding in `Protocol.php`
* Fix `SchemaAttribute` failure for PHPStan

PHP8 Support

• Allowing version 6.0 of the php-functional library to support PHP8

Schema Builder & Schema Generator

This release introduces the Schema builder & generator.

Thanks @fcoedno for these high quality hacktoberfest contributions!

Update `flix-tech/avro-php` dependency

Thanks to @nick-zh