fix: upgrade sequelize to latest version to fix CVE

Signed-off-by: BoHong Li <a60814billy@gmail.com>

package.json

@@ -31,7 +31,7 @@
     "codemirror": "git+https://github.com/hackmdio/CodeMirror.git",
     "compression": "^1.6.2",
     "connect-flash": "^0.1.1",
-    "connect-session-sequelize": "^4.1.0",
+    "connect-session-sequelize": "^6.0.0",
     "cookie": "0.3.1",
     "cookie-parser": "1.4.3",
     "deep-freeze": "^0.0.1",
@@ -113,8 +113,7 @@
     "scrypt-async": "^2.0.1",
     "scrypt-kdf": "^2.0.1",
     "select2": "^3.5.2-browserify",
-    "sequelize": "^3.28.0",
-    "sequelize-cli": "^2.5.1",
+    "sequelize": "5.3.2",
     "shortid": "2.2.8",
     "socket.io": "~2.1.1",
     "socket.io-client": "~2.1.1",
@@ -194,6 +193,7 @@
     "mocha": "^5.2.0",
     "mock-require": "^3.0.3",
     "optimize-css-assets-webpack-plugin": "^5.0.0",
+    "sequelize-cli": "^5.4.0",
     "script-loader": "^0.7.2",
     "string-loader": "^0.0.1",
     "style-loader": "^0.21.0",