Rewriting integrity attribute for resources that implement Subresource Integrity

[logpanic]

We recently ran across this issue in a site we're archiving.
The site has numerous resources that implement the subresource integrity feature. And as the file changes when its archived, the hash is no longer valid, and the resource is blocked from replay.

<link rel="stylesheet" media="print" href="https://assets.publishing.service.gov.uk/static/govuk-template-print-1076519521c2fffbbf75ab3b0d3b32ee2d96ac7e9778f1cdfac1771eefd1a1c0.css" crossorigin="anonymous" integrity="sha256-EHZRlSHC//u/das7DTsy7i2WrH6XePHN+sF3Hu/RocA=">

in IA's production version of Wayback, they've removed the hash from the integrity attribute

<link rel="stylesheet" media="print" href="https://web.archive.org/web/20171201195821cs_/https://assets.publishing.service.gov.uk/static/govuk-template-print-1076519521c2fffbbf75ab3b0d3b32ee2d96ac7e9778f1cdfac1771eefd1a1c0.css" crossorigin="anonymous" integrity="">

and from viewing pywb's code, it looks like the integrity attribute is either removed (https://github.com/webrecorder/pywb/blob/9c5673968c8067254d5dad72def5a8ddcd1b3fa0/pywb/static/wombat.js#L1515) or renamed (https://github.com/webrecorder/pywb/blob/develop/pywb/rewrite/html_rewriter.py#L323)

I'm proposing some type of rewrite feature that handles the integrity attribute for linked resources.