Added shared tsconfig.json to list of files to build when changed

refs https://github.com/TryGhost/DevOps/issues/45

- if this file changes, we presumably want to re-run any builds because
  it's possible the typescript config has changed

nx.json

@@ -15,7 +15,8 @@
     },
     "namedInputs": {
         "default": [
-            "{projectRoot}/**/*"
+            "{projectRoot}/**/*",
+            "{workspaceRoot}/ghost/tsconfig.json"
         ]
     },
     "targetDefaults": {