Bump big.js from 5.2.2 to 6.2.1

Bumps [big.js](https://github.com/MikeMcl/big.js) from 5.2.2 to 6.2.1.
- [Release notes](https://github.com/MikeMcl/big.js/releases)
- [Changelog](https://github.com/MikeMcl/big.js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/MikeMcl/big.js/compare/v5.2.2...v6.2.1)

---
updated-dependencies:
- dependency-name: big.js
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

package.json

@@ -23,7 +23,7 @@
     "assert-never": "^1.2.1",
     "axios": "^1.1.2",
     "basic-auth": "^2.0.0",
-    "big.js": "^5.2.2",
+    "big.js": "^6.2.1",
     "bitcore-lib": "^8.25.8",
     "bluebird": "^3.7.2",
     "body-parser": "^1.16.0",

yarn.lock

@@ -1588,10 +1588,10 @@ bech32@=1.1.3:
   resolved "https://registry.yarnpkg.com/bech32/-/bech32-1.1.3.tgz#bd47a8986bbb3eec34a56a097a84b8d3e9a2dfcd"
   integrity sha512-yuVFUvrNcoJi0sv5phmqc6P+Fl1HjRDRNOOkHY2X/3LBy2bIGNSFx4fZ95HMaXHupuS7cZR15AsvtmCIF4UEyg==
 
-big.js@^5.2.2:
-  version "5.2.2"
-  resolved "https://registry.yarnpkg.com/big.js/-/big.js-5.2.2.tgz#65f0af382f578bcdc742bd9c281e9cb2d7768328"
-  integrity sha512-vyL2OymJxmarO8gxMr0mhChsO9QGwhynfuu4+MHTAW6czfq9humCB7rKpUjDd9YUiDPU4mzpyupFSvOClAwbmQ==
+big.js@^6.2.1:
+  version "6.2.1"
+  resolved "https://registry.yarnpkg.com/big.js/-/big.js-6.2.1.tgz#7205ce763efb17c2e41f26f121c420c6a7c2744f"
+  integrity sha512-bCtHMwL9LeDIozFn+oNhhFoq+yQ3BNdnsLSASUxLciOb1vgvpHsIO1dsENiGMgbb4SkP5TrzWzRiLddn8ahVOQ==
 
 binary-extensions@^2.0.0:
   version "2.2.0"
@@ -2097,10 +2097,10 @@ command-exists@^1.2.6:
   resolved "https://registry.yarnpkg.com/command-exists/-/command-exists-1.2.9.tgz#c50725af3808c8ab0260fd60b01fbfa25b954f69"
   integrity sha512-LTQ/SGc+s0Xc0Fu5WaKnR0YiygZkm9eKFvyS+fRsU7/ZWFF8ykFM6Pc9aCVf1+xasOOZpO3BAVgVrKvsqKHV7w==
 
-commander@^5.0.0:
-  version "5.1.0"
-  resolved "https://registry.yarnpkg.com/commander/-/commander-5.1.0.tgz#46abbd1652f8e059bddaef99bbdcb2ad9cf179ae"
-  integrity sha512-P0CysNDQ7rtVw4QIQtm+MRxV66vKFSvlsQvGYXZWR3qFU0jlMKHZZZgw8e+8DSah4UDKMqnknRDQz+xuQXQ/Zg==
+commander@^6.2.0:
+  version "6.2.1"
+  resolved "https://registry.yarnpkg.com/commander/-/commander-6.2.1.tgz#0792eb682dfbc325999bb2b84fddddba110ac73c"
+  integrity sha512-U7VdrJFnJgo4xjrHpTzu0yrHPGImdsmD95ZlgYSEajAn2JKzDhDTPG9kBTefmObL2w/ngeZnilk+OV9CG3d7UA==
 
 commander@^7.2.0:
   version "7.2.0"