Revert "Bump cross-spawn from 6.0.5 to 7.0.1 (#117)"

This reverts commit a38dc59.

Author: lydell

package-lock.json

@@ -41,7 +41,7 @@
     "@typescript-eslint/eslint-plugin": "2.4.0",
     "@typescript-eslint/parser": "2.4.0",
     "babel-eslint": "10.0.3",
-    "cross-spawn": "7.0.1",
+    "cross-spawn": "6.0.5",
     "doctoc": "1.4.0",
     "eslint": "6.5.1",
     "eslint-config-google": "0.14.0",