CLI should let approve proposals when in execution stage

[martinvol]

Package

@celo/celocli

Have you ensured that all of these are up to date?

• [X] the package you are using

What version of the package are you on?

4

What command or function is the bug in?

celocli governance:approve

Operating System

None

Describe the bug

Previously, proposals where only approvable when they where in the approving stage. Nowadays, the approval stage doesn't exist anymore and rather they can be approved in both referendum and execution (source). But the cli only lets approve when in referendum stage (source).

[arthurgousset]

Great point, thanks for logging this @martinvol 👍

[aaronmgdr]

being done in #296