Merge option for existing rev-manifests

[manuelbieh]

In 0.8 it was possible to do something like:

const revAll = new $.revAll();

revAll.revisioner.manifest = require(path.resolve('./web/rev-manifest.json'));

return gulp.src([
    `./src/{css,images,js}/**/*.{jpg,gif,svg,png,css,js,map}`
])
.pipe(revAll.revision())
.pipe(gulp.dest('./web'))
.pipe(revAll.manifestFile({merge: true}))
.pipe(gulp.dest('./web));

... to merge an existing rev-manifest.json with the newly created by gulp-rev-all. This seems to be no longer possible in 0.9. I had a look at the source and it looks like there even is no chance to write a quick workaround for that.

Maybe I was just blind, so is it possible to just add files to an existing manifest instead of creating a new one replacing a possibly existing old one?