Bump xterm from 3.15.0-beta85 to 3.15.0-beta89 in /terminus-ter… (#1311)

Bumps [xterm](https://github.com/xtermjs/xterm.js) from 3.15.0-beta85 to 3.15.0-beta89.
- [Release notes](https://github.com/xtermjs/xterm.js/releases)
- [Commits](https://github.com/xtermjs/xterm.js/commits)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

terminus-terminal/package.json

@@ -28,7 +28,7 @@
     "runes": "^0.4.2",
     "slug": "^1.1.0",
     "uuid": "^3.3.2",
-    "xterm": "3.15.0-beta85",
+    "xterm": "3.15.0-beta89",
     "xterm-addon-fit": "^0.1.0-beta3",
     "xterm-addon-ligatures": "^0.1.0-beta-2",
     "xterm-addon-search": "^0.2.0-beta1",