feat: export ValidationError class instead of type

Author: L-Blondy

.gitignore

@@ -8,6 +8,7 @@ todo.*
 PR.md
 TEMP.md
 temp.ts
+.DS_store
 
 /app/dist
 

src/index.ts

@@ -10,4 +10,4 @@ export type {
 } from './types'
 export { up } from './up'
 export { isJsonifiable } from './utils'
-export { isValidationError, type ValidationError } from './validation-error'
+export { isValidationError, ValidationError } from './validation-error'