replace grunt-release with "release-it"

We expect release-it to be installed globally in order to make new releases.

Gruntfile.js

@@ -344,21 +344,6 @@ module.exports = function(grunt) {
       }
     },
 
-    release: {
-      options: {
-        additionalFiles: ['package-lock.json'],
-        tagName: 'v<%= version %>',
-        // the release 0.14.0 plugin is buggy and they are all done BEFORE the tagging, so we stick to 0.13.1 until a new proper release is done.
-        beforeRelease: ['clean', 'build'],
-        afterRelease: ['compress'],
-        npm: false,
-        github: {
-          repo: 'voidlabs/mosaico',
-          accessTokenVar: 'GITHUB_ACCESS_TOKEN',
-        }
-      },
-    },
-
   });
 
   grunt.registerTask('js', ['combineKOTemplates', 'browserify', 'exorcise', 'uglifyPrecheck:min']);

RELEASING.md

@@ -0,0 +1,9 @@
+We used grunt-release in past, but it's obsolete and misbehaving.
+
+So we now added release informations for release-it product to the package.json and expect the release to be manually done using release-it.
+
+npm install -g release-it
+
+release-it --dry-run
+
+release-it