chore: use math.Int instead of math.Int and apply linting (#12702)

* linting round

* fix changelog

* revert docs changes

* Update CHANGELOG.md

* revert an accidental change to security.md

* Update simapp/integration/client/grpc/tmservice/service_test.go

Co-authored-by: Julien Robert <julien@rbrt.fr>

x/staking/keeper/msg_server.go

@@ -2,10 +2,11 @@ package keeper
 
 import (
 	"context"
-	govtypes "github.com/cosmos/cosmos-sdk/x/gov/types"
 	"strconv"
 	"time"
 
+	govtypes "github.com/cosmos/cosmos-sdk/x/gov/types"
+
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"