Regenerate alertcenter client (googleapis#6918)

This PR was generated using Autosynth. 🌈


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

```
2021-01-26 03:37:14,848 synthtool [DEBUG] > Executing /home/kbuilder/.cache/synthtool/google-api-java-client-services/synth.py.
On branch autosynth-alertcenter
nothing to commit, working tree clean
2021-01-26 03:37:15,279 synthtool [DEBUG] > Cloning https://github.com/googleapis/discovery-artifact-manager.git.
DEBUG:synthtool:Cloning https://github.com/googleapis/discovery-artifact-manager.git.
2021-01-26 03:37:15,683 synthtool [DEBUG] > Cleaning output directory.
DEBUG:synthtool:Cleaning output directory.
2021-01-26 03:37:15,686 synthtool [DEBUG] > Installing dependencies.
DEBUG:synthtool:Installing dependencies.
2021-01-26 03:37:17,393 synthtool [INFO] > Generating alertcenter v1beta1.
INFO:synthtool:Generating alertcenter v1beta1.
2021-01-26 03:37:17,393 synthtool [INFO] > 	1.31.0
INFO:synthtool:	1.31.0
WARNING:root:object without properties Empty: OrderedDict([(u'description', u'A generic empty message that you can re-use to avoid defining duplicated empty messages in your APIs. A typical example is to use it as the request or the response type of an API method. For instance: service Foo { rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty); } The JSON representation for `Empty` is empty JSON object `{}`.'), (u'properties', OrderedDict()), (u'type', u'object'), (u'id', u'Empty')])
Writing json metadata to clients/google-api-services-alertcenter/v1beta1.metadata.json
2021-01-26 03:37:18,255 synthtool [DEBUG] > Wrote metadata to clients/google-api-services-alertcenter/synth.metadata.
DEBUG:synthtool:Wrote metadata to clients/google-api-services-alertcenter/synth.metadata.

```
</details>

Full log will be available here:
https://source.cloud.google.com/results/invocations/1a42608d-cd17-42ae-9390-c3421c65638c/targets

- [ ] To automatically regenerate this PR, check this box.

Author: yoshi-automation

clients/google-api-services-alertcenter/v1beta1.metadata.json

@@ -2,6 +2,6 @@
   "maven": {
     "groupId": "com.google.apis",
     "artifactId": "google-api-services-alertcenter",
-    "version": "v1beta1-rev20201231-1.31.0"
+    "version": "v1beta1-rev20210123-1.31.0"
   }
 }

clients/google-api-services-alertcenter/v1beta1/1.31.0/README.md

@@ -22,7 +22,7 @@ Add the following lines to your `pom.xml` file:
     <dependency>
       <groupId>com.google.apis</groupId>
       <artifactId>google-api-services-alertcenter</artifactId>
-      <version>v1beta1-rev20201231-1.31.0</version>
+      <version>v1beta1-rev20210123-1.31.0</version>
     </dependency>
   </dependencies>
 </project>
@@ -35,7 +35,7 @@ repositories {
   mavenCentral()
 }
 dependencies {
-  compile 'com.google.apis:google-api-services-alertcenter:v1beta1-rev20201231-1.31.0'
+  compile 'com.google.apis:google-api-services-alertcenter:v1beta1-rev20210123-1.31.0'
 }
 ```
 

clients/google-api-services-alertcenter/v1beta1/1.31.0/com/google/api/services/alertcenter/v1beta1/model/GoogleOperations.java

@@ -52,6 +52,14 @@ public final class GoogleOperations extends com.google.api.client.json.GenericJs
   @com.google.api.client.util.Key
   private java.lang.String description;
 
+  /**
+   * A header to display above the incident message. Typcially used to attach a localized notice on
+   * the timeline for followup comms translations.
+   * The value may be {@code null}.
+   */
+  @com.google.api.client.util.Key
+  private java.lang.String header;
+
   /**
    * A one-line incident description.
    * The value may be {@code null}.
@@ -112,6 +120,25 @@ public GoogleOperations setDescription(java.lang.String description) {
     return this;
   }
 
+  /**
+   * A header to display above the incident message. Typcially used to attach a localized notice on
+   * the timeline for followup comms translations.
+   * @return value or {@code null} for none
+   */
+  public java.lang.String getHeader() {
+    return header;
+  }
+
+  /**
+   * A header to display above the incident message. Typcially used to attach a localized notice on
+   * the timeline for followup comms translations.
+   * @param header header or {@code null} for none
+   */
+  public GoogleOperations setHeader(java.lang.String header) {
+    this.header = header;
+    return this;
+  }
+
   /**
    * A one-line incident description.
    * @return value or {@code null} for none

clients/google-api-services-alertcenter/v1beta1/1.31.0/pom.xml

@@ -8,8 +8,8 @@
 
   <groupId>com.google.apis</groupId>
   <artifactId>google-api-services-alertcenter</artifactId>
-  <version>v1beta1-rev20201231-1.31.0</version>
-  <name>Google Workspace Alert Center API v1beta1-rev20201231-1.31.0</name>
+  <version>v1beta1-rev20210123-1.31.0</version>
+  <name>Google Workspace Alert Center API v1beta1-rev20210123-1.31.0</name>
   <packaging>jar</packaging>
 
   <inceptionYear>2011</inceptionYear>