Move dependency loading to a function

lib/main.js

@@ -2,10 +2,26 @@
 
 // eslint-disable-next-line import/extensions, import/no-extraneous-dependencies
 import { CompositeDisposable } from 'atom';
-import fs from 'fs-plus';
-import path from 'path';
-import * as helpers from 'atom-linter';
-import semver from 'semver';
+
+let fs;
+let path;
+let helpers;
+let semver;
+
+function loadDeps() {
+  if (!semver) {
+    semver = require('semver');
+  }
+  if (!fs) {
+    fs = require('fs-plus');
+  }
+  if (!helpers) {
+    helpers = require('atom-linter');
+  }
+  if (!path) {
+    path = require('path');
+  }
+}
 
 // Local variables
 const parseRegex = /(\d+):(\d+):\s(([A-Z])\d{2,3})\s+(.*)/g;
@@ -82,14 +98,14 @@ const determineExecVersion = async (execPath) => {
   if (match !== null) {
     execPathVersions.set(execPath, match[0]);
   }
-}
+};
 
 const getFlake8Version = async (execPath) => {
   if (!execPathVersions.has(execPath)) {
     await determineExecVersion(execPath);
   }
   return execPathVersions.get(execPath);
-}
+};
 
 export default {
   activate() {
@@ -108,6 +124,7 @@ export default {
       if (typeof atom.config.get('linter-flake8.disableTimeout') !== 'undefined') {
         atom.config.unset('linter-flake8.disableTimeout');
       }
+      loadDeps();
     };
     packageDepsID = window.requestIdleCallback(linterFlake8Deps);
     this.idleCallbacks.add(packageDepsID);
@@ -160,6 +177,8 @@ export default {
       scope: 'file',
       lintOnFly: true,
       lint: async (textEditor) => {
+        loadDeps();
+
         const filePath = textEditor.getPath();
         const fileText = textEditor.getText();