Upgrade prost and prost-types to version 0.8.0 and tonic to version 0.5.0

[romac]

Closes: #1161

Depends on informalsystems/tendermint-rs#926

Description

• Upgrade prost and prost-types to version 0.8.0
• Upgrade tonic to version 0.5.0

---

For contributor use:

• Updated the Unreleased section of CHANGELOG.md with the issue.
• If applicable: Unit tests written, added test to CI.
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Updated relevant documentation (docs/) and code comments.
• Re-reviewed Files changed in the Github PR explorer.

[adizere]

Had a brief look and it's not clear why tests are failing.

I would have a slight preference for trying to do the release prior to merging this PR (despite the security warning around prost), and we'll figure out the CI failures later next week.

(As a minor point, it may also be desirable to postpone changes around .proto files because there's a parallel PR changing all .proto files -- #948) .

[adizere]

One more idea --

what if we just update the deps without regenerating the .proto files? That will make the PR easier to review and hopefully E2E tests will pass!

[romac]

what if we just update the deps without regenerating the .proto files? That will make the PR easier to review and hopefully E2E tests will pass!

Unfortunately, we cannot do that because the Rust code generated by Prost 0.7 is not forward-compatible with Prost 0.8.

[romac]

Looks like we are not receiving any events via the WS subscription anymore, ie. hermes listen ibc-[0|1] does not output anything.

[romac]

@thanethomson and I suspect that much of the breakage here and in tendermint-rs is due to a number of regressions in prost 0.8, notably this one.

Marking this PR as blocked until that happens.

[romac]

Superseded by #1451.