chore: regenerate README (#1530)

This PR was generated using Autosynth. 🌈 <details><summary>Log from Synthtool</summary> ``` 2021-08-24 23:30:16,489 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigquery/.github/readme/synth.py. On branch autosynth-readme nothing to commit, working tree clean 2021-08-24 23:30:17,732 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata. ``` </details> Full log will be available here: https://source.cloud.google.com/results/invocations/a2bd1d2d-d8a7-46fd-ad1f-a2ff282ddbaf/targets - [ ] To automatically regenerate this PR, check this box. (May take up to 24 hours.)

Author: yoshi-automation

.github/readme/synth.metadata/synth.metadata

@@ -4,14 +4,14 @@
  "git": {
  "name": ".",
  "remote": "https://github.com/googleapis/java-bigquery.git",
- "sha": "e1713f2cf04349cd0336cd3aca7ca2870bfa96d4"
+ "sha": "da09e53bbdd18693c182d7945506b0531bb445e4"
  }
  },
  {
  "git": {
  "name": "synthtool",
  "remote": "https://github.com/googleapis/synthtool.git",
- "sha": "8032ab5a32471d85ece8fc261df16cc40fbfa4fb"
+ "sha": "63cff634aabb85854caa511c5837ea6b45f42b4b"
  }
  }
  ]

README.md

@@ -21,7 +21,7 @@ See https://github.com/GoogleCloudPlatform/cloud-opensource-java/wiki/The-Google
  <dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>libraries-bom</artifactId>
- <version>20.9.0</version>
+ <version>21.0.0</version>
  <type>pom</type>
  <scope>import</scope>
  </dependency>