chore: regenerate content client (googleapis#29569)

Generated in GitHub action: https://togithub.com/googleapis/googleapis/google-api-java-client-services/actions/workflows/codegen.yaml

Author: yoshi-code-bot

clients/google-api-services-content/v2.1/2.0.0/README.md

@@ -1,6 +1,6 @@
 # Content API for Shopping Client Library for Java
 
-Manage your product listings and accounts for Google Shopping
+This API is deprecated. Please use Merchant API instead: https://developers.google.com/merchant/api. 
 
 This page contains information about getting started with the Content API for Shopping
 using the Google API Client Library for Java. In addition, you may be interested
@@ -22,7 +22,7 @@ Add the following lines to your `pom.xml` file:
     <dependency>
       <groupId>com.google.apis</groupId>
       <artifactId>google-api-services-content</artifactId>
-      <version>v2.1-rev20250723-2.0.0</version>
+      <version>v2.1-rev20250921-2.0.0</version>
     </dependency>
   </dependencies>
 </project>
@@ -35,7 +35,7 @@ repositories {
   mavenCentral()
 }
 dependencies {
-  implementation 'com.google.apis:google-api-services-content:v2.1-rev20250723-2.0.0'
+  implementation 'com.google.apis:google-api-services-content:v2.1-rev20250921-2.0.0'
 }
 ```
 

clients/google-api-services-content/v2.1/2.0.0/com/google/api/services/content/ShoppingContent.java

@@ -20,7 +20,7 @@
  * Service definition for ShoppingContent (v2.1).
  *
  * <p>
- * Manage your product listings and accounts for Google Shopping
+ * This API is deprecated. Please use Merchant API instead: https://developers.google.com/merchant/api. 
  * </p>
  *
  * <p>

clients/google-api-services-content/v2.1/2.0.0/pom.xml

@@ -8,8 +8,8 @@
 
   <groupId>com.google.apis</groupId>
   <artifactId>google-api-services-content</artifactId>
-  <version>v2.1-rev20250723-2.0.0</version>
-  <name>Content API for Shopping v2.1-rev20250723-2.0.0</name>
+  <version>v2.1-rev20250921-2.0.0</version>
+  <name>Content API for Shopping v2.1-rev20250921-2.0.0</name>
   <packaging>jar</packaging>
 
   <inceptionYear>2011</inceptionYear>

clients/google-api-services-content/v2.1/README.md

@@ -1,6 +1,6 @@
 # Content API for Shopping Client Library for Java
 
-Manage your product listings and accounts for Google Shopping
+This API is deprecated. Please use Merchant API instead: https://developers.google.com/merchant/api. 
 
 This page contains information about getting started with the Content API for Shopping
 using the Google API Client Library for Java. In addition, you may be interested
@@ -22,7 +22,7 @@ Add the following lines to your `pom.xml` file:
     <dependency>
       <groupId>com.google.apis</groupId>
       <artifactId>google-api-services-content</artifactId>
-      <version>v2.1-rev20250723-2.0.0</version>
+      <version>v2.1-rev20250921-2.0.0</version>
     </dependency>
   </dependencies>
 </project>
@@ -35,7 +35,7 @@ repositories {
   mavenCentral()
 }
 dependencies {
-  implementation 'com.google.apis:google-api-services-content:v2.1-rev20250723-2.0.0'
+  implementation 'com.google.apis:google-api-services-content:v2.1-rev20250921-2.0.0'
 }
 ```