chore: regenerate README (#983)

This PR was generated using Autosynth. 🌈


<details><summary>Log from Synthtool</summary>

```
2020-11-30 19:08:23,642 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-bigquery/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working directory clean
2020-11-30 19:08:24,696 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/91b9c857-dfe1-4348-aa1d-d09406e7a535/targets

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

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-bigquery.git",
-        "sha": "0cfc98bffc9970d3275cc233d59c621ddbb6aea6"
+        "sha": "d1189e5afece0d2aa57b84181ad8e097b36b4cd7"
       }
     },
     {

README.md

@@ -112,6 +112,7 @@ has instructions for running the samples.
 | Create External Table Aws | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/CreateExternalTableAws.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-bigquery&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/bigquery/CreateExternalTableAws.java) |
 | Create Iam Policy | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/CreateIamPolicy.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-bigquery&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/bigquery/CreateIamPolicy.java) |
 | Create Job | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/CreateJob.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-bigquery&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/bigquery/CreateJob.java) |
+| Create Materialized View | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/CreateMaterializedView.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-bigquery&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/bigquery/CreateMaterializedView.java) |
 | Create Model | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/CreateModel.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-bigquery&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/bigquery/CreateModel.java) |
 | Create Partitioned Table | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/CreatePartitionedTable.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-bigquery&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/bigquery/CreatePartitionedTable.java) |
 | Create Range Partitioned Table | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/CreateRangePartitionedTable.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-bigquery&page=editor&open_in_editor=samples/snippets/src/main/java/com/example/bigquery/CreateRangePartitionedTable.java) |