fix #436: Posting to Slack doesn't work

package.json

@@ -65,6 +65,7 @@
     "cookie-parser": "^1.4.3",
     "cross-env": "^5.0.5",
     "csrf": "~3.0.3",
+    "diff": "^3.5.0",
     "elasticsearch": "^15.0.0",
     "entities": "^1.1.1",
     "env-cmd": "^8.0.1",
@@ -130,7 +131,6 @@
     "css-loader": "^0.28.0",
     "csv-to-markdown-table": "^0.4.0",
     "date-fns": "^1.29.0",
-    "diff": "^3.3.0",
     "diff2html": "^2.3.3",
     "eazy-logger": "^3.0.2",
     "eslint": "^4.19.1",

yarn.lock

@@ -2238,10 +2238,14 @@ diff@3.3.1:
   version "3.3.1"
   resolved "https://registry.yarnpkg.com/diff/-/diff-3.3.1.tgz#aa8567a6eed03c531fc89d3f711cd0e5259dec75"
 
-diff@^3.1.0, diff@^3.3.0, diff@^3.3.1:
+diff@^3.1.0, diff@^3.3.1:
   version "3.4.0"
   resolved "https://registry.yarnpkg.com/diff/-/diff-3.4.0.tgz#b1d85507daf3964828de54b37d0d73ba67dda56c"
 
+diff@^3.5.0:
+  version "3.5.0"
+  resolved "https://registry.yarnpkg.com/diff/-/diff-3.5.0.tgz#800c0dd1e0a8bfbc95835c202ad220fe317e5a12"
+
 diffie-hellman@^5.0.0:
   version "5.0.2"
   resolved "https://registry.yarnpkg.com/diffie-hellman/-/diffie-hellman-5.0.2.tgz#b5835739270cfe26acf632099fded2a07f209e5e"