Remove 'qs' dependency

'qs' appears to be unused since 34c5598 (PR matrix-org#2719).

Signed-off-by: Clark Fischer <clark.fischer@gmail.com>

Author: clarkf

package.json

@@ -62,7 +62,6 @@
         "matrix-events-sdk": "0.0.1",
         "matrix-widget-api": "^1.0.0",
         "p-retry": "4",
-        "qs": "^6.9.6",
         "sdp-transform": "^2.14.1",
         "unhomoglyph": "^1.0.6",
         "uuid": "9"

yarn.lock

@@ -5872,13 +5872,6 @@ punycode@^2.1.0, punycode@^2.1.1:
   resolved "https://registry.yarnpkg.com/punycode/-/punycode-2.1.1.tgz#b58b010ac40c22c5657616c8d2c2c02c7bf479ec"
   integrity sha512-XRsRjdf+j5ml+y/6GKHPZbrF/8p2Yga0JPtdqTIY2Xe5ohJPD9saDJJLPvp9+NSBprVvevdXZybnj2cv8OEd0A==
 
-qs@^6.9.6:
-  version "6.11.0"
-  resolved "https://registry.yarnpkg.com/qs/-/qs-6.11.0.tgz#fd0d963446f7a65e1367e01abd85429453f0c37a"
-  integrity sha512-MvjoMCJwEarSbUYk5O+nmoSzSutSsTwF85zcHPQ9OrlFoZOYIjaqBAJIqIXjptyD5vThxGq52Xu/MaJzRkIk4Q==
-  dependencies:
-    side-channel "^1.0.4"
-
 querystring-es3@~0.2.0:
   version "0.2.1"
   resolved "https://registry.yarnpkg.com/querystring-es3/-/querystring-es3-0.2.1.tgz#9ec61f79049875707d69414596fd907a4d711e73"