Bump sockjs from 0.3.19 to 0.3.21 in /twistter-frontend

Bumps [sockjs](https://github.com/sockjs/sockjs-node) from 0.3.19 to 0.3.21.
- [Release notes](https://github.com/sockjs/sockjs-node/releases)
- [Changelog](https://github.com/sockjs/sockjs-node/blob/v0.3.21/Changelog)
- [Commits](https://github.com/sockjs/sockjs-node/compare/v0.3.19...v0.3.21)

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

README.md

@@ -1,14 +1,2 @@
 # CS307-Team24
 CS307 Team 24 Twistter website
-
-### Images
-<p>
-  <img alt="00.png" src="./screenshots/00.png" width="1000">
-  <img alt="01.png" src="./screenshots/01.png" width="1000">
-  <img alt="02.png" src="./screenshots/02.png" width="1000">
-  <img alt="03.png" src="./screenshots/03.png" width="1000">
-  <img alt="04.png" src="./screenshots/04.png" width="1000">
-  <img alt="05.png" src="./screenshots/05.png" width="1000">
-  <img alt="06.png" src="./screenshots/06.png" width="1000">
-  <img alt="07.png" src="./screenshots/07.png" width="1000">
-</p>

functions/package-lock.json

@@ -673,14 +673,6 @@
         "readable-stream": "~1.0.32"
       }
     },
-    "busboy": {
-      "version": "0.3.1",
-      "resolved": "https://registry.npmjs.org/busboy/-/busboy-0.3.1.tgz",
-      "integrity": "sha512-y7tTxhGKXcyBxRKAni+awqx8uqaJKrSFSNFSeRG5CsWNdmy2BIK+6VGWEW7TZnIO/533mtMEA4rOevQV815YJw==",
-      "requires": {
-        "dicer": "0.3.0"
-      }
-    },
     "bytebuffer": {
       "version": "5.0.1",
       "resolved": "https://registry.npmjs.org/bytebuffer/-/bytebuffer-5.0.1.tgz",
@@ -1918,6 +1910,10 @@
             "brace-expansion": "^1.1.7"
           }
         },
+        "minimist": {
+          "version": "1.2.0",
+          "bundled": true
+        },
         "minipass": {
           "version": "2.3.5",
           "bundled": true,
@@ -1933,6 +1929,19 @@
             "minipass": "^2.2.1"
           }
         },
+        "mkdirp": {
+          "version": "0.5.1",
+          "bundled": true,
+          "requires": {
+            "minimist": "0.0.8"
+          },
+          "dependencies": {
+            "minimist": {
+              "version": "0.0.8",
+              "bundled": true
+            }
+          }
+        },
         "ms": {
           "version": "2.1.2",
           "bundled": true
@@ -2726,16 +2735,18 @@
       }
     },
     "minimist": {
-      "version": "1.2.8",
-      "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.8.tgz",
-      "integrity": "sha512-2yyAR8qBkN3YuheJanUpWC5U3bb5osDywNB8RzDVlDwDHbocAJveqqj1u8+SVD7jkWT4yvsHCpWqqWqAxb0zCA=="
+      "version": "0.0.8",
+      "resolved": "https://registry.npmjs.org/minimist/-/minimist-0.0.8.tgz",
+      "integrity": "sha1-hX/Kv8M5fSYluCKCYuhqp6ARsF0=",
+      "dev": true
     },
     "mkdirp": {
-      "version": "0.5.6",
-      "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.6.tgz",
-      "integrity": "sha512-FP+p8RB8OWpF3YZBCrP5gtADmtXApB5AMLn+vdyA+PyxCjrCs00mjyUozssO33cwDeT3wNGdLxJ5M//YqtHAJw==",
+      "version": "0.5.1",
+      "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.1.tgz",
+      "integrity": "sha1-MAV0OOrGz3+MR2fzhkjWaX11yQM=",
+      "dev": true,
       "requires": {
-        "minimist": "^1.2.6"
+        "minimist": "0.0.8"
       }
     },
     "ms": {