Added memoryview support to frombytes()

[radarhere]

Resolves #6933. Alternative to #6937

Adds support for using memoryview objects in frombytes(), by changing

Pillow/src/decode.c

Line 124 in dbcd737

if (!PyArg_ParseTuple(args, "y#", &buffer, &bufsize)) {

to use y* instead. This is actually the "recommended way to accept binary data".

See https://bugs.python.org/issue30625 for a discussion about why this change allows memoryview objects to be accepted.

[Yay295]

I think this is missing a call to PyBuffer_Release().

[radarhere]

I've created PR #6976 to release the buffer.

[radarhere]

#6976 has now been merged.