Typo in Base2 rfc

[johnchandlerburnham]

In https://github.com/multiformats/multibase/blob/master/rfcs/Base2.md#encoding:

For example, [0x58, 0x59, 0x60] can be converted to multibase base2 as follows:

map each byte to the base2 representation:
 ["01011000", "01011001", "01011010"]

concatenate:
 "010110000101100101011010"

prefix with '0':
 "0010110000101100101011010"

The binary representation of 0x60 is 0b0110000. The third byte 0b01011010 in hexadecimal is 0x5A.