Squashed commit of the following:

commit 4b1a55a
Author: dependabot-preview[bot] <dependabot-preview[bot]@users.noreply.github.com>
Date:   Tue May 28 20:54:39 2019 +0000

    Bump iolazyload from 1.1.0 to 1.2.0

    Bumps [iolazyload](https://github.com/cdowdy/io-lazyload) from 1.1.0 to 1.2.0.
    - [Release notes](https://github.com/cdowdy/io-lazyload/releases)
    - [Commits](cdowdy/io-lazyload@v1.1.0...v1.2.0)

commit 4c34a83
Merge: 5496dcf 7934e54
Author: hangy <[email protected]>
Date:   Tue May 28 22:52:04 2019 +0200

    Merge branch 'master' of https://github.com/openfoodfacts/openfoodfacts-server

commit 5496dcf
Author: hangy <[email protected]>
Date:   Tue May 28 22:47:40 2019 +0200

    Update gulpfile to [email protected] syntax.

commit 8002312
Author: dependabot-preview[bot] <dependabot-preview[bot]@users.noreply.github.com>
Date:   Tue May 28 20:31:24 2019 +0000

    Bump gulp-sass from 3.2.1 to 4.0.2

    Bumps [gulp-sass](https://github.com/dlmanning/gulp-sass) from 3.2.1 to 4.0.2.
    - [Release notes](https://github.com/dlmanning/gulp-sass/releases)
    - [Changelog](https://github.com/dlmanning/gulp-sass/blob/master/CHANGELOG.md)
    - [Commits](dlmanning/gulp-sass@v3.2.1...v4.0.2)

commit 5381631
Author: dependabot-preview[bot] <dependabot-preview[bot]@users.noreply.github.com>
Date:   Tue May 28 20:24:04 2019 +0000

    Bump gulp from 3.9.1 to 4.0.2

    Bumps [gulp](https://github.com/gulpjs/gulp) from 3.9.1 to 4.0.2.
    - [Release notes](https://github.com/gulpjs/gulp/releases)
    - [Changelog](https://github.com/gulpjs/gulp/blob/master/CHANGELOG.md)
    - [Commits](gulpjs/gulp@v3.9.1...v4.0.2)

commit f8d1091
Author: Stéphane Gigandet <[email protected]>
Date:   Tue May 28 15:53:54 2019 +0000

    fix issues with labels taxonomy

commit 2d05aab
Author: dependabot-preview[bot] <dependabot-preview[bot]@users.noreply.github.com>
Date:   Tue May 28 05:29:33 2019 +0000

    Bump gulp-sourcemaps from 2.6.4 to 2.6.5

    Bumps [gulp-sourcemaps](https://github.com/gulp-sourcemaps/gulp-sourcemaps) from 2.6.4 to 2.6.5.
    - [Release notes](https://github.com/gulp-sourcemaps/gulp-sourcemaps/releases)
    - [Commits](gulp-sourcemaps/gulp-sourcemaps@v2.6.4...v2.6.5)

commit 3babf3a
Author: dependabot-preview[bot] <dependabot-preview[bot]@users.noreply.github.com>
Date:   Tue May 28 20:20:22 2019 +0000

    Bump eslint from 5.10.0 to 5.16.0

    Bumps [eslint](https://github.com/eslint/eslint) from 5.10.0 to 5.16.0.
    - [Release notes](https://github.com/eslint/eslint/releases)
    - [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
    - [Commits](eslint/eslint@v5.10.0...v5.16.0)

commit d9dc369
Author: dependabot-preview[bot] <dependabot-preview[bot]@users.noreply.github.com>
Date:   Tue May 28 05:30:04 2019 +0000

    Bump stylelint from 9.10.1 to 10.0.1

    Bumps [stylelint](https://github.com/stylelint/stylelint) from 9.10.1 to 10.0.1.
    - [Release notes](https://github.com/stylelint/stylelint/releases)
    - [Changelog](https://github.com/stylelint/stylelint/blob/master/CHANGELOG.md)
    - [Commits](stylelint/stylelint@9.10.1...10.0.1)

gulpfile.js

@@ -13,7 +13,7 @@ var sassOptions = {
   includePaths: ['./html/bower_components/foundation/scss']
 };
 
-gulp.task('sass', function() {
+gulp.task('default', function() {
   return gulp
     .src(input)
     .pipe(sourcemaps.init())
@@ -22,5 +22,3 @@ gulp.task('sass', function() {
     .pipe(sourcemaps.write('.'))
     .pipe(gulp.dest(output));
 });
-
-gulp.task('default', ['sass']);

package.json

@@ -49,10 +49,10 @@
     "components-jqueryui": "components/jqueryui#^1.12.1",
     "foundation-icon-fonts": "zurb/foundation-icon-fonts#*",
     "foundation-sites": "zurb/bower-foundation#^5.5.3",
-    "gulp": "^3.9.1",
+    "gulp": "^4.0.2",
     "gulp-clean-css": "^4.2.0",
-    "gulp-sass": "^3.1.0",
-    "gulp-sourcemaps": "^2.4.0",
+    "gulp-sass": "^4.0.2",
+    "gulp-sourcemaps": "^2.6.5",
     "iolazyload": "cdowdy/io-lazyload#^1.2.0",
     "leaflet": "Leaflet/Leaflet#>=1.5.1",
     "leaflet.markercluster": "Leaflet/Leaflet.markercluster#>=1.0.0",
@@ -63,8 +63,8 @@
     "opencollective": "^1.0.3"
   },
   "devDependencies": {
-    "eslint": "^5.6.1",
-    "stylelint": "^9.10.1",
+    "eslint": "^5.16.0",
+    "stylelint": "^10.0.1",
     "stylelint-config-recommended-scss": "^3.3.0",
     "stylelint-scss": "^3.6.1"
   },