dvc: Set max-line-length to 79 in .pylintrc (iterative#2578)

Adjust the `max-line-length` option to the same value used by black and `.flake8` file.

.pylintrc

@@ -314,7 +314,7 @@ indent-after-paren=4
 indent-string='    '
 
 # Maximum number of characters on a single line.
-max-line-length=100
+max-line-length=79
 
 # Maximum number of lines in a module.
 max-module-lines=1000