Use consistent max line lengths

Author: larrybradley

.flake8

@@ -1,3 +1,3 @@
 [flake8]
-max-line-length = 88
+max-line-length = 79
 exclude = extern

.pep8speaks.yml

@@ -2,7 +2,7 @@ scanner:
     linter: flake8
 
 flake8:
-  max-line-length: 88
+  max-line-length: 79
 
   exclude:
     - version.py

.pycodestyle

@@ -1,3 +1,3 @@
 [pycodestyle]
-max-line-length = 88
+max-line-length = 79
 exclude = extern

tox.ini

@@ -121,7 +121,7 @@ skip_install = true
 changedir = .
 description = check code style with flake8
 deps = flake8
-commands = flake8 photutils --count --max-line-length=100
+commands = flake8 photutils --count --max-line-length=79
 
 [testenv:pep517]
 skip_install = true