Remove unused statuspageio dependency

- It appears to be unused and the upstream project is seemingly unmaintained
- It also blocks installs when using versions of setuptools > 57.5.0
  due to the same issue described in: tikitu/jsmin#33

setup.py

@@ -18,7 +18,6 @@
     "markdown2>=2.3.7",
     "python-slugify>=1.2.6",
     "slackclient>=1.3,<2",
-    "statuspageio>=0.0.1",
 ]
 
 # allow setup.py to be run from any path