Bump http-proxy from 1.16.2 to 1.18.1 in /demo

Bumps [http-proxy](https://github.com/http-party/node-http-proxy) from 1.16.2 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@1.16.2...1.18.1)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

demo/package-lock.json

@@ -3207,13 +3207,9 @@ etag@~1.8.1:
   version "1.8.1"
   resolved "https://registry.yarnpkg.com/etag/-/etag-1.8.1.tgz#41ae2eeb65efa62268aebfea83ac7d79299b0887"
 
-[email protected]:
-  version "1.2.0"
-  resolved "https://registry.yarnpkg.com/eventemitter3/-/eventemitter3-1.2.0.tgz#1c86991d816ad1e504750e73874224ecf3bec508"
-
 eventemitter3@^4.0.0:
-  version "4.0.4"
-  resolved "https://registry.yarnpkg.com/eventemitter3/-/eventemitter3-4.0.4.tgz#b5463ace635a083d018bdc7c917b4c5f10a85384"
+  version "4.0.7"
+  resolved "https://registry.yarnpkg.com/eventemitter3/-/eventemitter3-4.0.7.tgz#2de9b68f6528d5644ef5c59526a1b4a07306169f"
 
 events@^3.0.0:
   version "3.1.0"
@@ -3540,10 +3536,8 @@ flush-write-stream@^1.0.0:
     readable-stream "^2.3.6"
 
 follow-redirects@^1.0.0:
-  version "1.11.0"
-  resolved "https://registry.yarnpkg.com/follow-redirects/-/follow-redirects-1.11.0.tgz#afa14f08ba12a52963140fe43212658897bc0ecb"
-  dependencies:
-    debug "^3.0.0"
+  version "1.13.0"
+  resolved "https://registry.yarnpkg.com/follow-redirects/-/follow-redirects-1.13.0.tgz#b42e8d93a2a7eea5ed88633676d6597bc8e384db"
 
 for-in@^1.0.2:
   version "1.0.2"
@@ -4084,14 +4078,7 @@ [email protected]:
     lodash "^4.17.11"
     micromatch "^3.1.10"
 
-http-proxy@^1.13.0:
-  version "1.16.2"
-  resolved "https://registry.yarnpkg.com/http-proxy/-/http-proxy-1.16.2.tgz#06dff292952bf64dbe8471fa9df73066d4f37742"
-  dependencies:
-    eventemitter3 "1.x.x"
-    requires-port "1.x.x"
-
-http-proxy@^1.17.0:
+http-proxy@^1.13.0, http-proxy@^1.17.0:
   version "1.18.1"
   resolved "https://registry.yarnpkg.com/http-proxy/-/http-proxy-1.18.1.tgz#401541f0534884bbf95260334e72f88ee3976549"
   dependencies:
@@ -7113,7 +7100,7 @@ require-package-name@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/require-package-name/-/require-package-name-2.0.1.tgz#c11e97276b65b8e2923f75dabf5fb2ef0c3841b9"
 
-requires-port@1.x.x, requires-port@^1.0.0:
+requires-port@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/requires-port/-/requires-port-1.0.0.tgz#925d2601d39ac485e091cf0da5c6e694dc3dcaff"