Fix an import from distutils that is problematic on recent Python versions.

Signed-off-by: Daira-Emma Hopwood <daira@jacaranda.org>

pyproject.toml

@@ -13,6 +13,7 @@ documentation = "https://github.com/zcash/developers/"
 classifiers = [
     "Private :: Do Not Upload",
 ]
+package-mode = false
 
 [tool.poetry.dependencies]
 python = "^3.8"
@@ -20,3 +21,4 @@ drest = "0.9.12"
 networkx = "3.1"
 pygraphviz = "1.11"
 sgqlc = "16.3"
+str2bool = "1.1"

zcash-issue-dag.py

@@ -7,7 +7,7 @@
 import drest
 import networkx as nx
 
-from distutils.util import strtobool
+from str2bool import str2bool as strtobool
 import mimetypes
 import os
 from textwrap import wrap