Adds pre-commit config to run various lintersci_improvements

This ads black, isort, pyupgrade, and flake8 to pre-commit-config.yaml
There are also some small changes to travis.yml and tasks.py to reduce
some repeated configurations that should be consolidated into
setup.cfg. Most other changes are automated by the linter scripts.

1 files changed, 1 insertions, 1 deletions

diff --git a/examples/unicode_commands.py b/examples/unicode_commands.py
index 0a7c5ac7..df02b028 100755
--- a/examples/unicode_commands.py
+++ b/examples/unicode_commands.py
@@ -16,7 +16,7 @@ class UnicodeApp(cmd2.Cmd):
 
     def do_𝛑print(self, _):
         """This command prints 𝛑 to 5 decimal places."""
-        self.poutput("𝛑 = {0:.6}".format(math.pi))
+        self.poutput("𝛑 = {:.6}".format(math.pi))
 
     def do_你好(self, arg):
         """This command says hello in Chinese (Mandarin)."""