Incomplete support of 0-9-1 field type values

[alvinyan-bond]

Describe the bug
The current version of the library does not support two field type values defined in the 0-9-1 spec: u for short-uint, and i for long-uint.

To Reproduce
This is not super trivial to reproduce, but any producer generating messages with u or i field types cause this error to be thrown: "invalid field or value inside of a frame". The error is thrown from https://github.com/rabbitmq/amqp091-go/blob/v1.10.0/read.go#L253 because these field types are not in the switch statement.

Expected behavior
I expected this library to support all field types defined in the AMQP-0-9-1 spec. See table on page 31 of https://www.rabbitmq.com/resources/specs/amqp0-9-1.pdf which includes u and i.

Screenshots
N/A - see code link above.

Desktop (please complete the following information):

• OS: Linux
• Browser: Chrome
• Version: N/A - not a browser issue

Additional context
It looks like this was originally reported in the streadway version of this repo, but was dropped and never addressed: streadway/amqp#391

[alvinyan-bond]

Python's Pika client supports these: https://github.com/pika/pika/blob/802a625299707ba800d3da910afd506beb5a9462/pika/data.py#L206

As does Node's ampqlib: https://github.com/amqp-node/amqplib/blob/28f1fd02170cc981dd69666dcc9f901c47a54ef2/lib/codec.js#L203

[lukebakken]

@alvinyan-bond it sounds like you have a good understanding of this issue. A pull request with a fix and tests would be appreciated. Thanks!