add missing arginfo

[remicollet]

Without this PR, reflection is missing important information

$ php  --re maxminddb
Extension [ <persistent> extension #113 maxminddb version 1.3.0 ] {

  - Classes [1] {
    Class [ <internal:maxminddb> class MaxMind\Db\Reader ] {

      - Constants [0] {
      }

      - Static properties [0] {
      }

      - Static methods [0] {
      }

      - Properties [0] {
      }

      - Methods [4] {
        Method [ <internal:maxminddb, ctor> public method __construct ] {
        }

        Method [ <internal:maxminddb> public method close ] {
        }

        Method [ <internal:maxminddb> public method get ] {
        }

        Method [ <internal:maxminddb> public method metadata ] {
        }
      }
    }
  }
}

With this PR

$ php -n -d extension=modules/maxminddb.so --re maxminddb
Extension [ <persistent> extension #15 maxminddb version 1.3.0 ] {

  - Classes [1] {
    Class [ <internal:maxminddb> class MaxMind\Db\Reader ] {

      - Constants [0] {
      }

      - Static properties [0] {
      }

      - Static methods [0] {
      }

      - Properties [0] {
      }

      - Methods [4] {
        Method [ <internal:maxminddb, ctor> public method __construct ] {

          - Parameters [1] {
            Parameter #0 [ <required> $db_file ]
          }
        }

        Method [ <internal:maxminddb> public method close ] {

          - Parameters [0] {
          }
        }

        Method [ <internal:maxminddb> public method get ] {

          - Parameters [1] {
            Parameter #0 [ <required> $ip_address ]
          }
        }

        Method [ <internal:maxminddb> public method metadata ] {

          - Parameters [0] {
          }
        }
      }
    }
  }
}

[oschwald]

Nice! Thanks!