No longer compatible with Node 8 after upgrading strip-comments

[calinoracation]

We recently started getting CI failures when the package change in #2280 got pulled in indirectly for us, which then resulted in failures with a message like below:

Invalid regular expression: /^(?<!(?:<!-))-->/: Invalid group

If you install the same npm packages on node 10, this works, and we use node 10 locally so we only saw it on CI for Node v8.9.1.

Library Affected:
workbox-webpack-plugin

Browser & Platform:
On build

Issue or Feature Request Description:
Downgrade strip-comments until we're sure it is compatible with Node v8.

[calinoracation]

FWIW, on strip-comments, they assert on the page that they are only node 10+ compatible.

Install with npm (requires Node.js >=10):

We were able to pin workbox-build to 5.0.0-rc.0 before this change occurred to minimize disruption, but that's only a temporary solution.

[jeffposnick]

Sorry about that—we do test against Node.js v8 in our automated suite, but I guess that particular code in the third-party module isn't being exercised 😦

Our intention is to support Node.js v8 in the Workbox v5 release, so I'll drop back down to the earlier version of strip-comments.

[codler]

Node 8 will have end of life this year end. https://nodejs.org/en/about/releases/ , wouldn't it be better to upgrade to newer node??

[jeffposnick]

Given that it's not Dec. 31 yet, supporting Node v8 for the Workbox v5 release remains our goal.