build: track flaky tests for "nightly", add new secrets for tagging (#…

…443)

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Synth log will be available here:
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Source-Link: googleapis/synthtool@8cf6d28

packages/google-cloud-texttospeech/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/nodejs-text-to-speech.git",
-        "sha": "a501f379a3eacade1d45d42b2537f28d1efe4b18"
+        "sha": "401c5e9307a3c4ad6439c2df68db37e095af78b6"
       }
     },
     {
@@ -19,7 +19,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "05de3e1e14a0b07eab8b474e669164dbd31f81fb"
+        "sha": "8cf6d2834ad14318e64429c3b94f6443ae83daf9"
       }
     }
   ],
@@ -51,7 +51,6 @@
     ".github/ISSUE_TEMPLATE/feature_request.md",
     ".github/ISSUE_TEMPLATE/support_request.md",
     ".github/PULL_REQUEST_TEMPLATE.md",
-    ".github/publish.yml",
     ".github/release-please.yml",
     ".github/workflows/ci.yaml",
     ".gitignore",