minor #857 Updating Yarn dependencies, making build process work again (bobdenotter)

This PR was merged into the master branch.

Discussion
----------

Updating Yarn dependencies, making build process work again

Some housekeeping on the Yarn / Encore build process:

 - Updated `symfony/encore` to `0.20.1` from `0.9.1`
 - Update a few other deps
 - Build process is now working again
 - Changed file naming strategy

Note: I replaced this

```
    .enableVersioning(false)
```

with this:

```
    .configureFilenames({
        js: '[name].js',
        images: 'images/[name].[ext]',
        fonts: 'fonts/[name].[ext]'
    })
```

I did this to keep the delta minimal. Since symfony/webpack-encore#110 `.enableVersioning(false)` is not doing what it says (for understandable reasons), but in this case I chose to keep the filenames without a versioning hash. If you think we should introduce filenames with version hashes instead, i'll happily update this PR.

Commits
-------

44d7267 Updating Yarn dependencies, making build process work again

Author: javiereguiluz

package.json

@@ -1,18 +1,18 @@
 {
   "devDependencies": {
-    "@symfony/webpack-encore": "^0.9.1",
-    "bloodhound-js": "^1.2.1",
+    "@symfony/webpack-encore": "^0.20.1",
+    "bloodhound-js": "^1.2.3",
     "bootstrap-sass": "^3.3.7",
     "bootstrap-tagsinput": "^0.7.1",
     "bootswatch": "^3.3.7",
     "eonasdan-bootstrap-datetimepicker": "^4.17.47",
     "font-awesome": "^4.7.0",
     "highlight.js": "^9.12.0",
-    "imports-loader": "^0.7.1",
-    "jquery": "^3.2.1",
+    "imports-loader": "^0.8.0",
+    "jquery": "^3.3.1",
     "lato-font": "^3.0.0",
-    "node-sass": "^4.5.3",
-    "sass-loader": "^6.0.5",
+    "node-sass": "^4.9.3",
+    "sass-loader": "^7.1.0",
     "typeahead.js": "^0.11.1"
   },
   "scripts": {