fix(validator): support multipart headers without a space separating …

…boundary (honojs#3286)

src/validator/validator.ts

@@ -24,7 +24,7 @@ export type ValidationFunction<
 type ExcludeResponseType<T> = T extends Response & TypedResponse<any> ? never : T
 
 const jsonRegex = /^application\/([a-z-\.]+\+)?json(;\s*[a-zA-Z0-9\-]+\=([^;]+))*$/
-const multipartRegex = /^multipart\/form-data(; boundary=[a-zA-Z0-9'"()+_,\-./:=?]+)?$/
+const multipartRegex = /^multipart\/form-data(;\s?boundary=[a-zA-Z0-9'"()+_,\-./:=?]+)?$/
 const urlencodedRegex = /^application\/x-www-form-urlencoded$/
 
 export const validator = <