Update mbed-coap to version 4.6.3

[anttiylitokola]

Description

• Bug fix: Remove timed out blockwise message from resend queue. If blockwise message was timed out message was still kept in the resend queue which causes unnecessary reconnections on client side.
• Documentation: Document all the available macros.

Pull request type

[X] Fix
[ ] Refactor
[ ] Target update
[ ] Functionality change
[ ] Breaking change

[anttiylitokola]

@yogpan01, please review.

[yogpan01]

Approved.
@0xc0170 @adbridge this issue has been reported while testing critical feature for one of our customer, something that we would need in RC2. Thanks!

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 3023
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/8020/

Triggering tests

/morph test
/morph export-build
/morph mbed2-build

[mbed-ci]

Test : SUCCESS

Build number : 2792
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/8020/2792

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2639
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/8020/