Update dependencies to fix known vulnerabilities

[fstani]

Updates version

Set bn.js to 4.12.2 and elliptic to 6.6.1

To fix: https://security.snyk.io/vuln/SNYK-JS-ELLIPTIC-8720086 https://security.snyk.io/vuln/SNYK-JS-ELLIPTIC-7577916 https://security.snyk.io/vuln/SNYK-JS-ELLIPTIC-7577917 https://security.snyk.io/vuln/SNYK-JS-ELLIPTIC-1064899 https://security.snyk.io/vuln/SNYK-JS-ELLIPTIC-571484

[fstani]

@ljharb Any chance we can accept these updates?

[ljharb]

There's no need for it at all - the fixed versions are all in-range. You just need to update your lockfiles.