build(deps): bump @cosmjs/* dependencies to 0.31.1

[manu0466]

Description

Closes #756
Closes #749
Closes #748
Closes #745
Closes #740
Closes #737
Closes #736

This PR updates the versions of all @cosmjs/* dependencies to 0.31.1.

Due to ongoing issues with the GitHub actions, the automated testing isn't functioning as expected. Here is a screenshot as evidence that the tests are successfully passing:

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