Update socket.io to version 2.0.4

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>

Author: SISheogorath

package.json

@@ -112,8 +112,8 @@
     "sequelize": "^3.28.0",
     "sequelize-cli": "^2.5.1",
     "shortid": "2.2.6",
-    "socket.io": "~1.7.2",
-    "socket.io-client": "~1.7.2",
+    "socket.io": "~2.0.4",
+    "socket.io-client": "~2.0.4",
     "spin.js": "^2.3.2",
     "sqlite3": "^3.1.8",
     "store": "^1.3.20",

public/views/hackmd/foot.ejs

@@ -12,7 +12,7 @@
 <script src="https://cdnjs.cloudflare.com/ajax/libs/mermaid/7.1.0/mermaid.min.js" integrity="sha256-M3OC0Q6g4/+Q4j73OvnsnA+lMkdAE5KgupRHqTiPbnI=" crossorigin="anonymous" defer></script>
 <script src="https://cdnjs.cloudflare.com/ajax/libs/emojify.js/1.1.0/js/emojify.min.js" integrity="sha256-VAB5tAlKBvgaxw8oJ1crWMVbdmBVl4mP/2M8MNRl+4E=" crossorigin="anonymous" defer></script>
 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.2/lodash.min.js" integrity="sha256-Cv5v4i4SuYvwRYzIONifZjoc99CkwfncROMSWat1cVA=" crossorigin="anonymous" defer></script>
-<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/1.7.2/socket.io.min.js" integrity="sha256-WKvqiY0jZHWQZIohYEmr9KUC5rEaYEOFTq+ByllJK8w=" crossorigin="anonymous" defer></script>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.0.4/socket.io.js" integrity="sha256-WPeFPWD3PZQUDrpFnDM1N2KadNVwCfNS4cCZ78b76T8=" crossorigin="anonymous" defer></script>
 <script src="https://cdnjs.cloudflare.com/ajax/libs/handlebars.js/4.0.6/handlebars.min.js" integrity="sha256-1O3BtOwnPyyRzOszK6P+gqaRoXHV6JXj8HkjZmPYhCI=" crossorigin="anonymous" defer></script>
 <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.9.0/highlight.min.js" integrity="sha256-KbfTjB0WZ8vvXngdpJGY3Yp3xKk+tttbqClO11anCIU=" crossorigin="anonymous" defer></script>
 <script src="https://cdnjs.cloudflare.com/ajax/libs/gist-embed/2.6.0/gist-embed.min.js" integrity="sha256-KyF2D6xPIJUW5sUDSs93vWyZm+1RzIpKCexxElmxl8g=" crossorigin="anonymous" defer></script>