Upgrade all npm dependencies

[jcheng5]

No description provided.

[jcheng5]

This is failing Travis because of the code coverage command in package.json, apparently this needs to be done differently now.

[wch]

I'm good with merging it if the problem is just the code coverage check in Travis. (I'm personally not convinced that code coverage is a particularly useful metric, anyway.)

[jcheng5]

Note to future-self:

I couldn't get istanbul to work again, but c8 does. However, once I got c8 working, then mochaTest in Gruntfile.js no longer worked. This was with Mocha 7.1.0 which has experimental ES module support, but the mochaTest plugin doesn't seem to work properly with that.

[jcheng5]

After CRAN release for Bootstrap and jQuery upgrade, I'll go ahead and merge this (after removing the code coverage command from ci, and upgrading all the deps again). Thanks.

[CLAassistant]

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