Fix ValueError when bmp images with 1 bit channels are decoded (fixes #773) (#784)

* Update utils.py

bitspercomponent =1 is defined and stores as a .btm worked when I tested it

* Update utils.py

() replaced with []

* Update CHANGELOG.md

added changes for pull request

* Update for flake

* Update CHANGELOG.md

* Update CHANGELOG.md

Co-authored-by: Pieter Marsman <pietermarsman@gmail.com>

CHANGELOG.md

@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Fixed
 
+- 'ValueError': when bmp images with 1 bit channel are decoded ([#773](https://github.com/pdfminer/pdfminer.six/issues/773))
 - `ValueError` when trying to decrypt empty metadata values ([#766](https://github.com/pdfminer/pdfminer.six/issues/766))
 - Sphinx errors during building of documentation ([#760](https://github.com/pdfminer/pdfminer.six/pull/760))
 - `TypeError` when getting default width of font ([#720](https://github.com/pdfminer/pdfminer.six/issues/720))

pdfminer/utils.py

@@ -132,7 +132,7 @@ def apply_png_predictor(
 
     Documentation: http://www.libpng.org/pub/png/spec/1.2/PNG-Filters.html
     """
-    if bitspercomponent != 8:
+    if bitspercomponent not in [8, 1]:
         msg = "Unsupported `bitspercomponent': %d" % bitspercomponent
         raise ValueError(msg)