update xterm to fix emacs (#6459)

Author: LabhanshAgrawal

package.json

@@ -52,7 +52,7 @@
     "stylis": "3.5.4",
     "uuid": "8.3.2",
     "webpack-cli": "4.9.2",
-    "xterm": "4.18.0",
+    "xterm": "4.19.0-beta.21",
     "xterm-addon-fit": "^0.5.0",
     "xterm-addon-ligatures": "0.6.0-beta.14",
     "xterm-addon-search": "^0.8.2",

yarn.lock

@@ -8002,10 +8002,10 @@ [email protected]:
   resolved "https://registry.npmjs.org/xterm-addon-webgl/-/xterm-addon-webgl-0.12.0-beta.27.tgz#afc5bc01d1ef3af9005fb9f6325a4db9c92aa8d9"
   integrity sha512-P948trotU8FMHtaA7C2x97VpLq6QLSjO53kWNvONS0/XwEKQBIYCI7Jfri2wcLgfQg6Cn4OQGLoj2YBK3MMyww==
 
-xterm@4.18.0:
-  version "4.18.0"
-  resolved "https://registry.npmjs.org/xterm/-/xterm-4.18.0.tgz#a1f6ab2c330c3918fb094ae5f4c2562987398ea1"
-  integrity sha512-JQoc1S0dti6SQfI0bK1AZvGnAxH4MVw45ZPFSO6FHTInAiau3Ix77fSxNx3mX4eh9OL4AYa8+4C8f5UvnSfppQ==
+xterm@4.19.0-beta.21:
+  version "4.19.0-beta.21"
+  resolved "https://registry.npmjs.org/xterm/-/xterm-4.19.0-beta.21.tgz#bcc603fdb496cae052a1c7c978c0efb531f8a8f3"
+  integrity sha512-WwtYP0U/NyU6Mw8JIMFHLo3+JUScOugQCqBiFdJHUoeisNEaZSwWV89mSekYLhh6iOgce7Xkq9GRPq1zPcaoYQ==
 
 y18n@^5.0.5:
   version "5.0.5"