Fix/check in discord (#905)

* fix: change to mchacks 10 in email templates

* fix: dates

* fix: move confirmation date +1 day

* Fix: check in discord

---------

Author: brarsanmol

assets/email/statusEmail/Checked-in.hbs

@@ -390,7 +390,7 @@
                                                 This email is to confirm your check-in at McHacks!
                                                 <br><br>
                                                 Don't forget to join the McHacks participants <a
-                                                    href="https://discord.com/invite/fqbjr43cKf"
+                                                    href="https://discord.com/invite/Sa5P8yDgR6"
                                                     style="-webkit-text-size-adjust:100%;-ms-text-size-adjust:100%;color:#F2463A;text-decoration:none;">Discord</a>
                                                 for announcements, to chat with other hackers, ask questions, and form
                                                 teams!