Bump node-fetch from 2.6.6 to 2.6.7 in /examples/hardhat

Bumps [node-fetch](https://github.com/node-fetch/node-fetch) from 2.6.6 to 2.6.7.
- [Release notes](https://github.com/node-fetch/node-fetch/releases)
- [Commits](node-fetch/node-fetch@v2.6.6...v2.6.7)

---
updated-dependencies:
- dependency-name: node-fetch
  dependency-type: indirect
...

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

Author: dependabot[bot]

examples/hardhat/yarn.lock

@@ -2086,9 +2086,9 @@ [email protected]:
     semver "^5.7.0"
 
 node-fetch@^2.6.0:
-  version "2.6.6"
-  resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-2.6.6.tgz#1751a7c01834e8e1697758732e9efb6eeadfaf89"
-  integrity sha512-Z8/6vRlTUChSdIgMa51jxQ4lrw/Jy5SOW10ObaA47/RElsAN2c5Pn8bTgFGWn/ibwzXTE8qwr1Yzx28vsecXEA==
+  version "2.6.7"
+  resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-2.6.7.tgz#24de9fba827e3b4ae44dc8b20256a379160052ad"
+  integrity sha512-ZjMPFEfVx5j+y2yF35Kzx5sF7kDzxuDj6ziH4FFbOp87zKDZNx8yExJIb05OGF4Nlt9IHFIMBkRl41VdvcNdbQ==
   dependencies:
     whatwg-url "^5.0.0"
 
@@ -2563,7 +2563,7 @@ [email protected]:
 tr46@~0.0.3:
   version "0.0.3"
   resolved "https://registry.yarnpkg.com/tr46/-/tr46-0.0.3.tgz#8184fd347dac9cdc185992f3a6622e14b9d9ab6a"
-  integrity sha1-gYT9NH2snNwYWZLzpmIuFLnZq2o=
+  integrity sha512-N3WMsuqV66lT30CrXNbEjx4GEwlow3v6rr4mCcv6prnfwhS01rkgyFdjPNBYd9br7LpXV1+Emh01fHnq2Gdgrw==
 
 "true-case-path@^2.2.1":
   version "2.2.1"
@@ -2638,12 +2638,12 @@ uuid@^8.3.2:
 webidl-conversions@^3.0.0:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/webidl-conversions/-/webidl-conversions-3.0.1.tgz#24534275e2a7bc6be7bc86611cc16ae0a5654871"
-  integrity sha1-JFNCdeKnvGvnvIZhHMFq4KVlSHE=
+  integrity sha512-2JAn3z8AR6rjK8Sm8orRC0h/bcl/DqL7tRPdGZ4I1CjdF+EaMLmYxBHyXuKL849eucPFhvBoxMsflfOb8kxaeQ==
 
 whatwg-url@^5.0.0:
   version "5.0.0"
   resolved "https://registry.yarnpkg.com/whatwg-url/-/whatwg-url-5.0.0.tgz#966454e8765462e37644d3626f6742ce8b70965d"
-  integrity sha1-lmRU6HZUYuN2RNNib2dCzotwll0=
+  integrity sha512-saE57nupxk6v3HY35+jzBwYa0rKSy0XR8JSxZPwgLr7ys0IBzhGviA1/TUGJLmSVqs8pb9AnvICXEuOHLprYTw==
   dependencies:
     tr46 "~0.0.3"
     webidl-conversions "^3.0.0"