fix(locale): export km (#3201)

Author: nidexingg

src/runtime/locale/index.ts

@@ -13,6 +13,7 @@ export { default as hi } from './hi'
 export { default as id } from './id'
 export { default as it } from './it'
 export { default as ja } from './ja'
+export { default as km } from './km'
 export { default as ko } from './ko'
 export { default as nb_no } from './nb_no'
 export { default as nl } from './nl'