Bump http-proxy from 1.18.0 to 1.18.1 in /demo

Bumps [http-proxy](https://github.com/http-party/node-http-proxy) from 1.18.0 to 1.18.1.
- [Release notes](https://github.com/http-party/node-http-proxy/releases)
- [Changelog](https://github.com/http-party/node-http-proxy/blob/master/CHANGELOG.md)
- [Commits](http-party/node-http-proxy@1.18.0...1.18.1)

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

demo/yarn.lock

@@ -3559,7 +3559,7 @@ debug@=3.1.0, debug@~3.1.0:
   dependencies:
     ms "2.0.0"
 
-debug@^3.0.0, debug@^3.1.1, debug@^3.2.5, debug@^3.2.6:
+debug@^3.1.1, debug@^3.2.5, debug@^3.2.6:
   version "3.2.6"
   resolved "https://registry.yarnpkg.com/debug/-/debug-3.2.6.tgz#e83d17de16d8a7efb7717edbe5fb10135eee629b"
   integrity sha512-mel+jf7nrtEl5Pn1Qx46zARXKDpBbvzezse7p7LqINmdoIk8PYP5SySaxEmYv6TZ0JyEKA1hsCId6DIhgITtWQ==
@@ -4443,9 +4443,9 @@ event-source-polyfill@^1.0.9:
   integrity sha512-+x0BMKTYwZcmGmlkHK0GsXkX1+otfEwqu3QitN0wmWuHaZniw3HeIx1k5OjWX3JUHQHlPS4yONol6eokS1ZAWg==
 
 eventemitter3@^4.0.0:
-  version "4.0.0"
-  resolved "https://registry.yarnpkg.com/eventemitter3/-/eventemitter3-4.0.0.tgz#d65176163887ee59f386d64c82610b696a4a74eb"
-  integrity sha512-qerSRB0p+UDEssxTtm6EDKcE7W4OaoisfIMl4CngyEhjpYglocpNg6UEqCvemdGhosAsg4sO2dXJOdyBifPGCg==
+  version "4.0.7"
+  resolved "https://registry.yarnpkg.com/eventemitter3/-/eventemitter3-4.0.7.tgz#2de9b68f6528d5644ef5c59526a1b4a07306169f"
+  integrity sha512-8guHBZCwKnFhYdHr2ysuRWErTwhoN2X8XELRlrRwpmfeY2jjuUN4taQMsULKUVo1K4DvZl+0pgfyoysHxvmvEw==
 
 events@^3.0.0:
   version "3.0.0"
@@ -5025,11 +5025,9 @@ follow-redirects@1.5.10:
     debug "=3.1.0"
 
 follow-redirects@^1.0.0:
-  version "1.9.0"
-  resolved "https://registry.yarnpkg.com/follow-redirects/-/follow-redirects-1.9.0.tgz#8d5bcdc65b7108fe1508649c79c12d732dcedb4f"
-  integrity sha512-CRcPzsSIbXyVDl0QI01muNDu69S8trU4jArW9LpOt2WtC6LyUJetcIrmfHsRBx7/Jb6GHJUiuqyYxPooFfNt6A==
-  dependencies:
-    debug "^3.0.0"
+  version "1.13.0"
+  resolved "https://registry.yarnpkg.com/follow-redirects/-/follow-redirects-1.13.0.tgz#b42e8d93a2a7eea5ed88633676d6597bc8e384db"
+  integrity sha512-aq6gF1BEKje4a9i9+5jimNFIpq4Q1WiwBToeRK5NvZBd/TRsmW8BsJfOEGkr76TbOyPVD3OVDN910EcUNtRYEA==
 
 for-each@^0.3.3:
   version "0.3.3"
@@ -6141,9 +6139,9 @@ http-proxy-middleware@0.19.1:
     micromatch "^3.1.10"
 
 http-proxy@^1.17.0:
-  version "1.18.0"
-  resolved "https://registry.yarnpkg.com/http-proxy/-/http-proxy-1.18.0.tgz#dbe55f63e75a347db7f3d99974f2692a314a6a3a"
-  integrity sha512-84I2iJM/n1d4Hdgc6y2+qY5mDaz2PUVjlg9znE9byl+q0uC3DeByqBGReQu5tpLK0TAqTIXScRUV+dg7+bUPpQ==
+  version "1.18.1"
+  resolved "https://registry.yarnpkg.com/http-proxy/-/http-proxy-1.18.1.tgz#401541f0534884bbf95260334e72f88ee3976549"
+  integrity sha512-7mz/721AbnJwIVbnaSv1Cz3Am0ZLT/UBwkC92VlxhXv/k/BBQfM2fXElQNC27BVGr0uwUpplYPQM9LnaBMR5NQ==
   dependencies:
     eventemitter3 "^4.0.0"
     follow-redirects "^1.0.0"