Bump acorn from 5.7.3 to 5.7.4 in /example

Bumps [acorn](https://github.com/acornjs/acorn) from 5.7.3 to 5.7.4.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](acornjs/acorn@5.7.3...5.7.4)

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

Author: dependabot[bot]

example/yarn.lock

@@ -1685,26 +1685,16 @@ acorn-walk@^6.0.1, acorn-walk@^6.2.0:
   integrity sha512-7evsyfH1cLOCdAzZAd43Cic04yKydNx0cF+7tiA19p1XnLLPU4dpCQOqpjqwokFe//vS0QqfqqjCS2JkiIs0cA==
 
 acorn@^5.5.3:
-  version "5.7.3"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.3.tgz#67aa231bf8812974b85235a96771eb6bd07ea279"
-  integrity sha512-T/zvzYRfbVojPWahDsE5evJdHb3oJoQfFbsrKM7w5Zcs++Tr257tia3BmMP8XYVjp1S9RZXQMh7gao96BlqZOw==
+  version "5.7.4"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.4.tgz#3e8d8a9947d0599a1796d10225d7432f4a4acf5e"
+  integrity sha512-1D++VG7BhrtvQpNbBzovKNc1FLGGEE/oGe7b9xJm/RFHMBeUaUGpluV9RLjZa47YFdPcDAenEYuq9pQPcMdLJg==
 
-acorn@^6.0.1, acorn@^6.0.4, acorn@^6.2.1:
-  version "6.3.0"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.3.0.tgz#0087509119ffa4fc0a0041d1e93a417e68cb856e"
-  integrity sha512-/czfa8BwS88b9gWQVhc8eknunSA2DoJpJyTQkhheIf5E48u1N0R4q/YxxsAeqRrmK9TQ/uYfgLDfZo91UlANIA==
-
-acorn@^6.0.5, acorn@^6.3.0, acorn@^6.4.1:
+acorn@^6.0.1, acorn@^6.0.4, acorn@^6.0.5, acorn@^6.2.1, acorn@^6.3.0, acorn@^6.4.1:
   version "6.4.1"
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.4.1.tgz#531e58ba3f51b9dacb9a6646ca4debf5b14ca474"
   integrity sha512-ZVA9k326Nwrj3Cj9jlh3wGFutC2ZornPNARZwsNYqQYgN0EsV2d53w5RN/co65Ohn4sUAUtb1rSUAOD6XN9idA==
 
-acorn@^7.0.0:
-  version "7.0.0"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.0.0.tgz#26b8d1cd9a9b700350b71c0905546f64d1284e7a"
-  integrity sha512-PaF/MduxijYYt7unVGRuds1vBC9bFxbNf+VWqhOClfdgy7RlVkQqt610ig1/yxTgsDIfW1cWDel5EBbOy3jdtQ==
-
-acorn@^7.1.0, acorn@^7.1.1:
+acorn@^7.0.0, acorn@^7.1.0, acorn@^7.1.1:
   version "7.4.0"
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-7.4.0.tgz#e1ad486e6c54501634c6c397c5c121daa383607c"
   integrity sha512-+G7P8jJmCHr+S+cLfQxygbWhXy+8YTVGzAkpEbcLo2mLoL7tij/VG41QSHACSf5QgYRhMZYHuNc6drJaO0Da+w==
@@ -10760,7 +10750,7 @@ resolve@1.x, resolve@^1.11.1, resolve@^1.12.0, resolve@^1.13.1, resolve@^1.17.0:
     schema-utils "^1.0.0"
     semver "^5.7.1"
     semver-compare "^1.0.0"
-    serialize-javascript "^1.8.0"
+    serialize-javascript "^3.1.0"
     set-blocking "^2.0.0"
     set-value "^2.0.1"
     setimmediate "^1.0.5"
@@ -10890,7 +10880,7 @@ resolve@1.x, resolve@^1.11.1, resolve@^1.12.0, resolve@^1.13.1, resolve@^1.17.0:
     y18n "^4.0.0"
     yallist "^3.0.3"
     yargs "^13.3.0"
-    yargs-parser "^10.1.0"
+    yargs-parser "^13.1.2"
 
 restore-cursor@^2.0.0:
   version "2.0.0"
@@ -11266,7 +11256,7 @@ send@0.17.1:
     range-parser "~1.2.1"
     statuses "~1.5.0"
 
-serialize-javascript@^1.6.1, serialize-javascript@^1.8.0:
+serialize-javascript@^1.6.1:
   version "1.9.1"
   resolved "https://registry.yarnpkg.com/serialize-javascript/-/serialize-javascript-1.9.1.tgz#cfc200aef77b600c47da9bb8149c943e798c2fdb"
   integrity sha512-0Vb/54WJ6k5v8sSWN09S0ora+Hnr+cX40r9F170nT+mSkaxltoE/7R3OrIdBSUv1OoiobH1QoWQbCnAO+e8J1A==
@@ -11276,6 +11266,13 @@ serialize-javascript@^1.7.0:
   resolved "https://registry.yarnpkg.com/serialize-javascript/-/serialize-javascript-1.8.0.tgz#9515fc687232e2321aea1ca7a529476eb34bb480"
   integrity sha512-3tHgtF4OzDmeKYj6V9nSyceRS0UJ3C7VqyD2Yj28vC/z2j6jG5FmFGahOKMD9CrglxTm3tETr87jEypaYV8DUg==
 
+serialize-javascript@^3.1.0:
+  version "3.1.0"
+  resolved "https://registry.yarnpkg.com/serialize-javascript/-/serialize-javascript-3.1.0.tgz#8bf3a9170712664ef2561b44b691eafe399214ea"
+  integrity sha512-JIJT1DGiWmIKhzRsG91aS6Ze4sFUrYbltlkg2onR5OrnNM02Kl/hnY/T4FN2omvyeBbQmMJv+K4cPOpGzOTFBg==
+  dependencies:
+    randombytes "^2.1.0"
+
 serialize-javascript@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/serialize-javascript/-/serialize-javascript-4.0.0.tgz#b525e1238489a5ecfc42afacc3fe99e666f4b1aa"
@@ -13164,6 +13161,14 @@ yargs-parser@^13.1.1:
     camelcase "^5.0.0"
     decamelize "^1.2.0"
 
+yargs-parser@^13.1.2:
+  version "13.1.2"
+  resolved "https://registry.yarnpkg.com/yargs-parser/-/yargs-parser-13.1.2.tgz#130f09702ebaeef2650d54ce6e3e5706f7a4fb38"
+  integrity sha512-3lbsNRf/j+A4QuSZfDRA7HRSfWrzO0YjqTJd5kjAq37Zep1CEgaYmrH9Q3GwPiB9cHyd1Y1UwggGhJGoxipbzg==
+  dependencies:
+    camelcase "^5.0.0"
+    decamelize "^1.2.0"
+
 yargs@12.0.2:
   version "12.0.2"
   resolved "https://registry.yarnpkg.com/yargs/-/yargs-12.0.2.tgz#fe58234369392af33ecbef53819171eff0f5aadc"