feat(token registry): proto max collateral share (#1096)

## Description

ref: #1095

---

### Author Checklist

_All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues._

I have...

- [x] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [x] added `!` to the type prefix if API or client breaking change
- [x] added appropriate labels to the PR
- [x] targeted the correct branch (see [PR Targeting](https://github.com/umee-network/umee/blob/main/CONTRIBUTING.md#pr-targeting))
- [x] provided a link to the relevant issue or specification
- [x] added a changelog entry to `CHANGELOG.md`
- [x] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [x] updated the relevant documentation or specification
- [x] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

_All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items._

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed all author checklist items have been addressed
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

CHANGELOG.md

@@ -58,6 +58,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 - [913](https://github.com/umee-network/umee/pull/913) Changed update registry gov proposal to add and update tokens, but never delete them.
 - [918](https://github.com/umee-network/umee/pull/918) Add MarketSummary query to CLI.
 - [1068](https://github.com/umee-network/umee/pull/1068) Add a cache layer for token registry.
+- [1096](https://github.com/umee-network/umee/pull/1096) Add `max_collateral_share` to the x/leverage token registry.
 - [1094](https://github.com/umee-network/umee/pull/1094) Added TotalCollateral query.
 - [1099](https://github.com/umee-network/umee/pull/1099) Added TotalBorrowed query.
 

proto/umee/leverage/v1/leverage.proto

@@ -139,4 +139,13 @@ message Token {
   // and enable_msg_borrow set to false. Such tokens can be safely removed from the
   // oracle and price feeder as well.
   bool blacklist = 14;
+
+  // Maximum collateral share specifies how much of the
+  // system's overall collateral be provided by a single token.
+  // Value is a percent; allowed values are in [0, 100] range.
+  // 100 means that the token has no restriction. 10 means maximum 10% of total
+  // collateral value can provided by this token.
+  uint32 max_collateral_share = 15 [
+    (gogoproto.moretags) = "yaml:\"max_collateral_share\""
+  ];
 }

x/leverage/spec/02_state.md

@@ -49,5 +49,6 @@ type Token struct {
     EnableMsgSupply      bool
     EnableMsgBorrow      bool
     Blacklist            bool
+    MaxCollateralShare   uint32
 }
 ```

x/leverage/types/token.go

@@ -84,6 +84,10 @@ func (t Token) Validate() error {
 		}
 	}
 
+	if t.MaxCollateralShare > 100 {
+		return sdkerrors.ErrInvalidRequest.Wrap("Token.MaxCollateralShare must be in [0; 100] range")
+	}
+
 	return nil
 }