Added test case for CCITTFaxDecoder (#700)
Added test case for CCITTFaxDecoder (#700)

* array.array.tostring -> array.array.tobytes

The tostring method has been deprecated since Python 3.2 and was
removed altogether in 3.9. In Python 3.2 the method was renamed
to "tobytes"

Will close #641

* changelog entry

* test for tobytes

* Fix CHANGELOG.md

* Update CHANGELOG.md to PR that I can push on

* Simplify tests

Co-authored-by: Forest Gregg <26987b49d224f9a0afaaa425ae38b15d3e9d4c78@uchicago.edu>
pdfminer/pdfminer.six