chore: release 3.4.0 (#464)

Author: release-please[bot]

speech/package.json

@@ -11,7 +11,7 @@
     "test": "mocha system-test --timeout 600000"
   },
   "dependencies": {
-    "@google-cloud/speech": "^3.3.2",
+    "@google-cloud/speech": "^3.4.0",
     "@google-cloud/storage": "^4.0.0",
     "chalk": "^3.0.0",
     "node-record-lpcm16": "^1.0.1",