cleanup: remove dep lodash.pickBy

It turns out that the code calling this was unreachable.

Author: ofrobots

package-lock.json

@@ -32,7 +32,6 @@
     "bindings": "^1.2.1",
     "delay": "^4.0.1",
     "findit2": "^2.2.3",
-    "lodash.pickby": "^4.6.0",
     "nan": "^2.12.1",
     "node-pre-gyp": "^0.12.0",
     "p-limit": "^2.0.0",
@@ -43,7 +42,6 @@
     "split": "^1.0.1"
   },
   "devDependencies": {
-    "@types/lodash.pickby": "^4.6.5",
     "@types/mocha": "^5.0.0",
     "@types/node": "^10.0.3",
     "@types/p-limit": "^2.0.0",

package.json

@@ -18,7 +18,6 @@ import * as crypto from 'crypto';
 import * as events from 'events';
 import * as fs from 'fs';
 import * as path from 'path';
-import pickBy = require('lodash.pickby');
 
 // TODO: Make this more precise.
 const findit: (dir: string) => events.EventEmitter = require('findit2');
@@ -40,7 +39,6 @@ export interface ScanStats {
 export interface ScanResults {
   errors(): Map<string, Error>;
   all(): ScanStats;
-  selectStats(regex: RegExp): ScanStats;
   selectFiles(regex: RegExp, baseDir: string): string[];
   hash?: string;
 }
@@ -73,18 +71,6 @@ class ScanResultsImpl implements ScanResults {
     return this.stats;
   }
 
-  /**
-   * Used to get the file scan results for only the files
-   * whose filenames match the specified regex.
-   *
-   * @param {regex} regex The regex that tests a filename
-   *  to determine if the scan results for that filename
-   *  should be included in the returned results.
-   */
-  selectStats(regex: RegExp): ScanStats|{} {
-    return pickBy(this.stats, (_, key) => regex.test(key));
-  }
-
   /**
    * Used to get the only the file paths in the scan results
    * where the filenames match the specified regex and are