Feature: Add pickCommand command

filePicker.pickCommand will prompt the user for a file (as in
filePicker.pick) and then run a shell command. The file resulting from
the file prompt can be substituted into the command by inserting
"${file}" in the command string, similar to other variable
substitutions.

Author: danf-extrahop

package-lock.json

@@ -48,11 +48,11 @@
     "devDependencies": {
         "@types/node": "^8.10.66",
         "tslint": "^5.11.0",
-        "typescript": "^2.6.1",
+        "typescript": "^2.9.2",
         "vscode": "^1.1.21"
     },
     "dependencies": {
         "@types/glob": "^7.1.1",
         "glob": "^7.1.7"
     }
-}
+}