feature #960 Update Encore and tweak some of its settings (Lyrkan)

This PR was merged into the master branch.

Discussion
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Update Encore and tweak some of its settings

This PR:

* Updates the version of Encore to `^0.26`
* Updates the related bundle to `^1.4`
* Fixes the imported font paths that were not working anymore due to [the recent `resolve-url-loader` update](symfony/webpack-encore#540)
* Enables integrity hashes by default
* Adds `core-js@3` and configures Babel properly so polyfills are automatically added to the resulting build
* Disables file versioning when not in production mode (which prevented from using the dev-server)

Commits
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8ee0df5 Update Encore and tweak some of its settings

assets/scss/app.scss

@@ -3,6 +3,10 @@
 // see https://github.com/thomaspark/bootswatch/issues/55#issuecomment-298093182
 $web-font-path: 'data:text/css;base64,';
 
+// Make sure the bootstrap-sass and lato fonts are resolved correctly
+$icon-font-path: "~bootstrap-sass/assets/fonts/bootstrap/";
+$lato-font-path: '~lato-font/fonts';
+
 @import "~bootswatch/flatly/variables";
 @import "~bootstrap-sass/assets/stylesheets/bootstrap";
 @import "~bootswatch/flatly/bootswatch";

composer.json

@@ -26,7 +26,7 @@
         "symfony/translation": "*",
         "symfony/twig-bundle": "*",
         "symfony/validator": "*",
-        "symfony/webpack-encore-bundle": "^1.1",
+        "symfony/webpack-encore-bundle": "^1.4",
         "symfony/yaml": "*",
         "tgalopin/html-sanitizer-bundle": "^1.1",
         "twig/extensions": "^1.5",

package.json

@@ -1,10 +1,11 @@
 {
   "devDependencies": {
-    "@symfony/webpack-encore": "^0.22.0",
+    "@symfony/webpack-encore": "^0.26.0",
     "bloodhound-js": "^1.2.3",
     "bootstrap-sass": "^3.3.7",
     "bootstrap-tagsinput": "^0.7.1",
     "bootswatch": "^3.3.7",
+    "core-js": "^3.0.0",
     "eonasdan-bootstrap-datetimepicker": "^4.17.47",
     "font-awesome": "^4.7.0",
     "highlight.js": "^9.12.0",