refactor(error): use error module

src/lib/error.js

@@ -1,7 +0,0 @@
-module.exports = class SemanticReleaseError extends Error {
-  constructor (message, code) {
-    super()
-    this.message = message
-    this.code = code
-  }
-}

src/lib/type.js

@@ -1,4 +1,4 @@
-const SemanticReleaseError = require('./error')
+const SemanticReleaseError = require('@semantic-release/error')
 
 module.exports = function (plugins, commits, lastRelease, cb) {
   plugins.analyzeCommits(commits, (err, type) => {

src/lib/verify.js

@@ -1,4 +1,4 @@
-const SemanticReleaseError = require('./error')
+const SemanticReleaseError = require('@semantic-release/error')
 
 module.exports = function (pkg, options, env) {
   let errors = []