Remove migration announcement

Author: cytopia

docs/_includes/snippets/__ANNOUNCEMENTS__.rst

@@ -1,7 +0,0 @@
-.. raw:: html
-
-   <div style="background-color:#dddcb7; border: 3px solid #DA111A; padding:10px 20px; margin-bottom:20px;">
-       <h1 style="margin-bottom:15px;">Important Announcement</h1>
-       <p style="margin:5px;">Everybody is strongly encouraged to switch to the upcoming v1.0.0 release version to prevent unforseen issues upon merge to master.</p>
-       <p style="margin:5px;"><strong>Instructions here:</strong> <a target="_blank" href="https://github.com/cytopia/devilbox/pull/416">https://github.com/cytopia/devilbox/pull/416</a>.</p>
-   </div>