update dependencies

Pipfile

@@ -23,7 +23,6 @@ imap-tools = "*"
 langdetect = "*"
 # numpy 1.20.0 drops python 3.6 support
 numpy = "~=1.19.5"
-pdftotext = "*"
 pathvalidate = "*"
 # pinned to 8.1.0, since aarch64 wheels might not be available beyond that https://github.com/python-pillow/Pillow/issues/5202
 pillow = "==8.1.0"
@@ -55,6 +54,7 @@ concurrent-log-handler = "*"
 uvloop = "~=0.14.0"
 # TODO: keep an eye on piwheel builds and update this once available (https://www.piwheels.org/project/cryptography/)
 cryptography = "~=3.3.2"
+"pdfminer.six" = "*"
 
 [dev-packages]
 coveralls = "*"