vendor: update all dependencies to latest versions

vendor/google.golang.org/api/adexchangebuyer/v1.2/adexchangebuyer-api.json

@@ -1,12 +1,12 @@
 {
  "kind": "discovery#restDescription",
- "etag": "\"YWOzh2SDasdU84ArJnpYek-OMdg/0_pkDGZUigw6P9-q8PUQy4V9Lvo\"",
+ "etag": "\"YWOzh2SDasdU84ArJnpYek-OMdg/-1DKqIhPUpLfO8DBj8P3gNrIPtE\"",
  "discoveryVersion": "v1",
  "id": "adexchangebuyer:v1.2",
  "name": "adexchangebuyer",
  "canonicalName": "Ad Exchange Buyer",
  "version": "v1.2",
- "revision": "20170504",
+ "revision": "20170810",
  "title": "Ad Exchange Buyer API",
  "description": "Accesses your bidding-account information, submits creatives for validation, finds available direct deals, and retrieves performance reports.",
  "ownerDomain": "google.com",
@@ -21,7 +21,7 @@
  "basePath": "/adexchangebuyer/v1.2/",
  "rootUrl": "https://www.googleapis.com/",
  "servicePath": "adexchangebuyer/v1.2/",
- "batchPath": "batch",
+ "batchPath": "batch/adexchangebuyer/v1.2",
  "parameters": {
   "alt": {
    "type": "string",