chore: start tracking obsolete files (#92)

diff --git a/synth.metadata b/synth.metadata
index 9f65b73..8b2b29d 100644
--- a/synth.metadata
+++ b/synth.metadata
@@ -3,16 +3,78 @@
     {
       "git": {
         "name": ".",
-        "remote": "git@github.com:googleapis/python-api-core",
-        "sha": "db8e636f545a8872f959e3f403cfec30ffed6c34"
+        "remote": "https://github.com/googleapis/python-api-core.git",
+        "sha": "a85533903c57be4809fe76435e298409e0903931"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "0c868d49b8e05bc1f299bc773df9eb4ef9ed96e9"
+        "sha": "487eba79f8260e34205d8ceb1ebcc65685085e19"
       }
     }
+  ],
+  "generatedFiles": [
+    ".github/CONTRIBUTING.md",
+    ".github/ISSUE_TEMPLATE/bug_report.md",
+    ".github/ISSUE_TEMPLATE/feature_request.md",
+    ".github/ISSUE_TEMPLATE/support_request.md",
+    ".github/PULL_REQUEST_TEMPLATE.md",
+    ".github/release-please.yml",
+    ".github/snippet-bot.yml",
+    ".gitignore",
+    ".kokoro/build.sh",
+    ".kokoro/continuous/common.cfg",
+    ".kokoro/continuous/continuous.cfg",
+    ".kokoro/docker/docs/Dockerfile",
+    ".kokoro/docker/docs/fetch_gpg_keys.sh",
+    ".kokoro/docs/common.cfg",
+    ".kokoro/docs/docs-presubmit.cfg",
+    ".kokoro/docs/docs.cfg",
+    ".kokoro/populate-secrets.sh",
+    ".kokoro/presubmit/common.cfg",
+    ".kokoro/presubmit/presubmit.cfg",
+    ".kokoro/publish-docs.sh",
+    ".kokoro/release.sh",
+    ".kokoro/release/common.cfg",
+    ".kokoro/release/release.cfg",
+    ".kokoro/samples/lint/common.cfg",
+    ".kokoro/samples/lint/continuous.cfg",
+    ".kokoro/samples/lint/periodic.cfg",
+    ".kokoro/samples/lint/presubmit.cfg",
+    ".kokoro/samples/python3.6/common.cfg",
+    ".kokoro/samples/python3.6/continuous.cfg",
+    ".kokoro/samples/python3.6/periodic.cfg",
+    ".kokoro/samples/python3.6/presubmit.cfg",
+    ".kokoro/samples/python3.7/common.cfg",
+    ".kokoro/samples/python3.7/continuous.cfg",
+    ".kokoro/samples/python3.7/periodic.cfg",
+    ".kokoro/samples/python3.7/presubmit.cfg",
+    ".kokoro/samples/python3.8/common.cfg",
+    ".kokoro/samples/python3.8/continuous.cfg",
+    ".kokoro/samples/python3.8/periodic.cfg",
+    ".kokoro/samples/python3.8/presubmit.cfg",
+    ".kokoro/test-samples.sh",
+    ".kokoro/trampoline.sh",
+    ".kokoro/trampoline_v2.sh",
+    ".trampolinerc",
+    "CODE_OF_CONDUCT.md",
+    "CONTRIBUTING.rst",
+    "LICENSE",
+    "MANIFEST.in",
+    "docs/_static/custom.css",
+    "docs/_templates/layout.html",
+    "docs/conf.py",
+    "docs/multiprocessing.rst",
+    "renovate.json",
+    "scripts/decrypt-secrets.sh",
+    "scripts/readme-gen/readme_gen.py",
+    "scripts/readme-gen/templates/README.tmpl.rst",
+    "scripts/readme-gen/templates/auth.tmpl.rst",
+    "scripts/readme-gen/templates/auth_api_key.tmpl.rst",
+    "scripts/readme-gen/templates/install_deps.tmpl.rst",
+    "scripts/readme-gen/templates/install_portaudio.tmpl.rst",
+    "testing/.gitignore"
   ]
 }
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