chore(py-library): enable snippet-bot

Co-authored-by: Benjamin E. Coe <bencoe@google.com>

Source-Author: Takashi Matsuo <tmatsuo@google.com>
Source-Date: Tue Sep 1 17:14:08 2020 +0000
Source-Repo: googleapis/synthtool
Source-Sha: d91dd8aac77f7a9c5506c238038a26fa4f9e361e
Source-Link: googleapis/synthtool@d91dd8a

synth.metadata

@@ -19,14 +19,14 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "94421c47802f56a44c320257b2b4c190dc7d6b68"
+        "sha": "d91dd8aac77f7a9c5506c238038a26fa4f9e361e"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "94421c47802f56a44c320257b2b4c190dc7d6b68"
+        "sha": "d91dd8aac77f7a9c5506c238038a26fa4f9e361e"
       }
     }
   ],
@@ -58,6 +58,7 @@
     ".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",