npm run build generates untracked files

[marthacryan]

To reproduce:

• clone the plotly.js repo or git clean
• npm i
• npm run build
• git status
• This is the output:

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
	modified:   dist/plotly-basic.js
	modified:   dist/plotly-cartesian.js
	modified:   dist/plotly-finance.js
	modified:   dist/plotly-geo.js
	modified:   dist/plotly-gl2d.js
	modified:   dist/plotly-gl3d.js
	modified:   dist/plotly-mapbox.js
	modified:   dist/plotly-strict.js
	modified:   dist/plotly-with-meta.js
	modified:   dist/plotly.js

We should add these files to the git repo.