fix: upgrade to versions of coverage/instrument that solve out-of-bound errors (#349)

Author: bcoe

package.json

@@ -80,9 +80,9 @@
     "find-up": "^1.1.2",
     "foreground-child": "^1.5.3",
     "glob": "^7.0.3",
-    "istanbul-lib-coverage": "^1.0.0-alpha.4",
+    "istanbul-lib-coverage": "^1.0.0",
     "istanbul-lib-hook": "^1.0.0-alpha.4",
-    "istanbul-lib-instrument": "^1.1.0-alpha.3",
+    "istanbul-lib-instrument": "^1.1.0",
     "istanbul-lib-report": "^1.0.0-alpha.3",
     "istanbul-lib-source-maps": "^1.0.0-alpha.10",
     "istanbul-reports": "^1.0.0-alpha.8",