Update references to plugins in example repos / preprocessor repos

[chrisbreiding]

In anticipation of changing the plugins nomenclature to background, need to update all example repos and repos like the preprocessor repos that references plugins.

[chrisbreiding]

• cypress-webpack-preprocessor
• cypress-browserify-preprocessor
• cypress-parcel-preprocessor
• cypress-watch-preprocessor
• cypress-example-recipes
• cypress-example-kitchensink
• cypress-example-todomvc
• cypress-example-api-testing
• cypress-example-docker-codeship
• cypress-example-group
• cypress-example-parallel

[emilyrohrbough]

Changes coming in 10.0 will replaces plugins with a nodeEvents concept. This is no longer applicable.