Workbox v6.4.0

Workbox v6.4.0 includes:

🎉 What's New?

• We upgraded to TypeScript 4.4.3. This required us to declare inline some types that are now longer part of the TypeScript standard; see #2946 for more context. [#2950]

worbox-background-sync

• You can check the number of requests in the sync queue with the new method size(). [#2941]

🐛 What's Fixed?

• We upgraded @surma/rollup-plugin-off-main to patch a vulnerability from the dependency. [#2962]
• A missing sourcemap is no longer a fatal error when running injectManifest. It returns now returns a warning and continues with execution. [#2959]

🎁 Thank you

To our new contributors in this version: @StephanBijzitter and @fuzail-ahmed!