message: feat(core): move secp256k1 to regular dependencies
  There should be no issues if the dependency cannot be compiled
  > This module provides native bindings to bitcoin-core/secp256k1. In
  browser elliptic will be used as fallback.
  Issue:
diff: "ripple-lib": "^1.4.1",
  "sanitize-html": "^1.27.5",
  "secrets.js-grempe": "^1.1.0",
  + "secp256k1": "^4.0.2",
  "stellar-sdk": "^8.1.0",
  "superagent": "^3.8.3",
  "superagent-proxy": "^2.1.0"
  "optionalDependencies": {
  "ethereumjs-abi": "^0.6.5",
  "ethereumjs-tx": "^1.3.7",
  - "ethereumjs-util": "^4.4.1",
  - "secp256k1": "^4.0.2"
  + "ethereumjs-util": "^4.4.1"
  },
  "nyc": {
  "extension": [
  