vs task to find missing stubs

Author: Jeff Flater

.vscode/tasks.json

@@ -1,6 +1,14 @@
 {
     "version": "2.0.0",
     "tasks": [
+      {
+        "label": "Behave: Find Missing Steps",
+        "type": "shell",
+        "command": "behave test/features --dry-run",
+        "problemMatcher": [],
+        "group": "test",
+        "detail": "Finds missing steps and prints stub implementations"
+      },
       {
         "label": "Docker: Build Behave Image",
         "type": "shell",