chore: add memo in ics20 packet data (cosmos#2411)

[alizahidraja]

Description

Add memo field in ics20 packet data proto
closes: #2411

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Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[alizahidraja]

Full disclosure: I couldn't manage to update packet.pb.go file from cli (generate code from proto file), so for now, I updated the file manually (not ideal, especially when the file starts with "do not edit")

I updated the corresponding code in keeper & types for transfer; if someone can help me generate the packet.pb.go file from cli, that would be great!

[crodriguezvega]

Hi @alizahidraja. Thanks a lot for picking this up. Unfortunately, there was already a couple of branches opened here and here implementing the changes. I am sorry that the issue was not properly assigned and gave the impression that it was available. We should have assigned it immediately to the person that was already working on it.

Is it ok if we close this PR then? I am very sorry for the confusion. If you're interested in working on ibc-go issues, please take a look at our good first issues and help wanted issues. We hope you can find one interesting for you; otherwise, let us know and I am sure we will be able to find something else!

[alizahidraja]

Hey @crodriguezvega! No worries at all :D

And yes, I will take a look at the ones with the mentioned tags