docs: use an array of strings as authors in proposal metadata (backport

#14472) (#14474)

Co-authored-by: Larry Engineer <26318510+larry0x@users.noreply.github.com>
Co-authored-by: Julien Robert <julien@rbrt.fr>

CHANGELOG.md

@@ -45,6 +45,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (x/gov, x/group) [#14472](https://github.com/cosmos/cosmos-sdk/pull/14356) The recommended metadata format for x/gov and x/group proposals now uses an array of strings (instead of a single string) for the `authors` field.
 * (crypto) [#14460](https://github.com/cosmos/cosmos-sdk/pull/14460) Check the signature returned by a ledger device against the public key in the keyring.
 * (x/gov) [#14390](https://github.com/cosmos/cosmos-sdk/pull/14390) Add title, proposer and summary to proposal struct
 * [#14356](https://github.com/cosmos/cosmos-sdk/pull/14356) Add `events.GetAttributes` and `event.GetAttribute` methods to simplify the retrieval of an attribute from event(s).

x/gov/README.md

@@ -2590,7 +2590,7 @@ Location: off-chain as json object stored on IPFS (mirrors [group proposal](../g
 ```json
 {
   "title": "",
-  "authors": "",
+  "authors": [""],
   "summary": "",
   "details": "",
   "proposal_forum_url": "",

x/group/README.md

@@ -2099,7 +2099,7 @@ Location: off-chain as json object stored on IPFS (mirrors [gov proposal](../gov
 ```json
 {
   "title": "",
-  "authors": "",
+  "authors": [""],
   "summary": "",
   "details": "",
   "proposal_forum_url": "",