The warnings about use of the unsafe Buffer constructor have been
addressed by package updates and patches.
The updates were:
* `gulp-sourcemaps` was updated from v2 to v3, and was patched to
replace remaining uses of the `Buffer` constructor
* Upstream PR: https://github.com/gulp-sourcemaps/gulp-sourcemaps/pull/388
* The transitive dependency `yazl` was updated from v2.4.3 to v2.5.1
in the lockfile.
* The abandoned packages `combine-source-map` and `inline-source-map`
were patched.
