fix: insert entry during iterating over a map (#3398)

Signed-off-by: fukua95 <fukua95@gmail.com>

command.go

@@ -3584,15 +3584,14 @@ func (c *cmdsInfoCache) Get(ctx context.Context) (map[string]*CommandInfo, error
 			return err
 		}
 
+		lowerCmds := make(map[string]*CommandInfo, len(cmds))
+
 		// Extensions have cmd names in upper case. Convert them to lower case.
 		for k, v := range cmds {
-			lower := internal.ToLower(k)
-			if lower != k {
-				cmds[lower] = v
-			}
+			lowerCmds[internal.ToLower(k)] = v
 		}
 
-		c.cmds = cmds
+		c.cmds = lowerCmds
 		return nil
 	})
 	return c.cmds, err