build: update docs and release scripts (#439)

* chore: update cloud rad kokoro build job

Delete `SharePoint` item from TOC.

Source-Author: F. Hinkelmann <franziska.hinkelmann@gmail.com>
Source-Date: Tue Aug 11 11:25:41 2020 -0400
Source-Repo: googleapis/synthtool
Source-Sha: bd0deaa1113b588d70449535ab9cbf0f2bd0e72f
Source-Link: googleapis/synthtool@bd0deaa

* build: perform publish using Node 12

Source-Author: Benjamin E. Coe <bencoe@google.com>
Source-Date: Wed Aug 12 12:12:29 2020 -0700
Source-Repo: googleapis/synthtool
Source-Sha: 5747555f7620113d9a2078a48f4c047a99d31b3e
Source-Link: googleapis/synthtool@5747555

packages/google-cloud-texttospeech/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/nodejs-text-to-speech.git",
-        "sha": "e6e41b84ec9adcbb4a68ba2c1f3969c427f85a93"
+        "sha": "7feac343aee1c44bf3f8fb80b9e27fe5f43ec821"
       }
     },
     {
@@ -19,7 +19,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "94421c47802f56a44c320257b2b4c190dc7d6b68"
+        "sha": "5747555f7620113d9a2078a48f4c047a99d31b3e"
       }
     }
   ],