chore: regenerate README (#985)

This PR was generated using Autosynth. 🌈


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

```
2020-11-30 20:08:11,353 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 20:08:12,370 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/d00c74f6-b386-4587-96c9-9624c9611fc9/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": "37c0632500366006aecab18b21a10bf8956c4b6c"
+        "sha": "5b0c7a2fd80f571b3b128b158c403673cca722cb"
       }
     },
     {

README.md

@@ -129,6 +129,7 @@ has instructions for running the samples.
 | Delete Dataset And Contents | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/DeleteDatasetAndContents.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/DeleteDatasetAndContents.java) |
 | Delete Label Dataset | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/DeleteLabelDataset.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/DeleteLabelDataset.java) |
 | Delete Label Table | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/DeleteLabelTable.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/DeleteLabelTable.java) |
+| Delete Materialized View | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/DeleteMaterializedView.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/DeleteMaterializedView.java) |
 | Delete Model | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/DeleteModel.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/DeleteModel.java) |
 | Delete Routine | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/DeleteRoutine.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/DeleteRoutine.java) |
 | Delete Table | [source code](https://github.com/googleapis/java-bigquery/blob/master/samples/snippets/src/main/java/com/example/bigquery/DeleteTable.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/DeleteTable.java) |