Enable HDLC frames > 255 bytes

[MarcelloZanghieri2]

Allow HDLC frames longer than 255 bytes.

[mrv96]

Hi,

whitout this PR the library breaks if HDLC frames longer than 255 due to the rising of the following exception:

ValueError: byte must be in range(0, 256)

Could you merge this PR?

Thank you

[mrv96]

Actually the fix can also be applied to the upstream method

Gurux.DLMS.Python/Gurux.DLMS.python/gurux_dlms/GXByteBuffer.py

Lines 217 to 224 in dfe1cd3

	def setUInt8(self, item, index=None):
	if index is None:
	self.setUInt8(item, self.size)
	self.size += 1
	else:
	if index >= self.capacity:
	self.capacity = index + self.__ARRAY_CAPACITY
	self._data[index] = item

The other methods like setInt8() seems to be already ok.