chore(deps): update dependency promise-retry to v2 (#1875)

Author: renovate-bot

functions/billing/package.json

@@ -21,7 +21,7 @@
     "@google-cloud/functions-framework": "^1.1.1",
     "child-process-promise": "^2.2.1",
     "mocha": "^7.0.0",
-    "promise-retry": "^1.1.1",
+    "promise-retry": "^2.0.0",
     "proxyquire": "^2.1.0",
     "request": "^2.88.0",
     "requestretry": "^4.0.0",

functions/helloworld/package.json

@@ -30,7 +30,7 @@
     "express": "^4.16.3",
     "mocha": "^7.0.0",
     "moment": "^2.24.0",
-    "promise-retry": "^1.1.1",
+    "promise-retry": "^2.0.0",
     "proxyquire": "^2.1.0",
     "request": "^2.88.0",
     "requestretry": "^4.0.0",