Travis tests fail

[htdat]

Travis tests in the recent PRs fail https://github.com/Automattic/Edit-Flow/pulls?q=is%3Apr+ but they worked well before.

Detailed errors

• Oldest https://travis-ci.org/github/Automattic/Edit-Flow/jobs/743803874

gyp ERR! build error 
gyp ERR! stack Error: `make` failed with exit code: 2
gyp ERR! stack     at ChildProcess.onExit (/home/travis/build/Automattic/Edit-Flow/node_modules/node-gyp/lib/build.js:262:23)
gyp ERR! stack     at ChildProcess.emit (node:events:329:20)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (node:internal/child_process:277:12)
gyp ERR! System Linux 4.4.0-101-generic
gyp ERR! command "/home/travis/.nvm/versions/node/v15.2.0/bin/node" "/home/travis/build/Automattic/Edit-Flow/node_modules/node-gyp/bin/node-gyp.js" "rebuild" "--verbose" "--libsass_ext=" "--libsass_cflags=" "--libsass_ldflags=" "--libsass_library="
gyp ERR! cwd /home/travis/build/Automattic/Edit-Flow/node_modules/node-sass
gyp ERR! node -v v15.2.0
gyp ERR! node-gyp -v v3.8.0
gyp ERR! not ok 
Build failed with error code: 1
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! node-sass@4.13.0 postinstall: `node scripts/build.js`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the node-sass@4.13.0 postinstall script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

• Latest https://travis-ci.org/github/Automattic/Edit-Flow/jobs/762039246

First errors

npm ERR! code 1
npm ERR! path /home/travis/build/Automattic/Edit-Flow/node_modules/node-sass
npm ERR! command failed

[htdat]

Closing this issue, and deferring to #634