chore(deps): bump @openzeppelin/contracts from 3.4.0 to 3.4.2

Bumps [@openzeppelin/contracts](https://github.com/OpenZeppelin/openzeppelin-contracts) from 3.4.0 to 3.4.2.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-contracts/releases)
- [Changelog](https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/CHANGELOG.md)
- [Commits](OpenZeppelin/openzeppelin-contracts@v3.4.0...v3.4.2)

---
updated-dependencies:
- dependency-name: "@openzeppelin/contracts"
  dependency-type: direct:production
...

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

Author: dependabot[bot]

contracts/package.json

@@ -13,7 +13,7 @@
     "deploy:xdai": "hardhat deploy --network xdai"
   },
   "dependencies": {
-    "@openzeppelin/contracts": "^3.4.0"
+    "@openzeppelin/contracts": "^3.4.2"
   },
   "devDependencies": {
     "@nomiclabs/hardhat-ethers": "^2.0.1",

yarn.lock

@@ -1955,10 +1955,10 @@
     "@types/sinon-chai" "^3.2.3"
     "@types/web3" "1.0.19"
 
-"@openzeppelin/contracts@^3.4.0":
-  version "3.4.0"
-  resolved "https://registry.yarnpkg.com/@openzeppelin/contracts/-/contracts-3.4.0.tgz#9a1669ad5f9fdfb6e273bb5a4fed10cb4cc35eb0"
-  integrity sha512-qh+EiHWzfY/9CORr+eRUkeEUP1WiFUcq3974bLHwyYzLBUtK6HPaMkIUHi74S1rDTZ0sNz42DwPc5A4IJvN3rg==
+"@openzeppelin/contracts@^3.4.2":
+  version "3.4.2"
+  resolved "https://registry.yarnpkg.com/@openzeppelin/contracts/-/contracts-3.4.2.tgz#d81f786fda2871d1eb8a8c5a73e455753ba53527"
+  integrity sha512-z0zMCjyhhp4y7XKAcDAi3Vgms4T2PstwBdahiO0+9NaGICQKjynK3wduSRplTgk4LXmoO1yfDGO5RbjKYxtuxA==
 
 "@resolver-engine/core@^0.3.3":
   version "0.3.3"