Replace staticFileGlobs by globPatterns in webpack config

[supertanuki]

In the "Get Started > webpack" page (https://workboxjs.org/get-started/webpack.html) there is an error in the config:

- staticFileGlobs: ['**/*.{html,js,css}'],
+ globPatterns: ['**/*.{html,js,css}'],

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[supertanuki]

I signed it!

[googlebot]

CLAs look good, thanks!

[jeffposnick]

Thanks!

[jeffposnick]

(I'm going to make the same change in gulp.md in a separate PR.)