build: add sideEffects: false to package.json

[sofisl]

Allows compilers to throw away unused requires.

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[bcoe]

This LGTM, is there a way that we could write a test for this in the library, so that we confirm it has the desired effect?

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[mhio]

Should sideEffects be boolean false ? esbuild is complaining about it since the 128.0.0 release:

▲ [WARNING] The value for "sideEffects" must be a boolean or an array [package.json]

    ./node_modules/googleapis/package.json:9:17:
      9 │   "sideEffects": "false",
        ╵                  ^

1 warning

Webpack documents it similarly as boolean | string[]