chore(editorconfig): add max_line_length for python files (#3225)

Set max_line_length to 79 for Python files to match PEP 8 and the
project's yapf configuration.

Co-authored-by: Esun Kim <[email protected]>

Author: rkuester

.editorconfig

@@ -19,6 +19,7 @@ indent_size = 2
 # https://google.github.io/styleguide/pyguide.html but 2-space indent
 indent_style = space
 indent_size = 2
+max_line_length = 79
 
 [WORKSPACE,BUILD,*.bzl]
 # https://bazel.build/build/style-guide