Release Google.Cloud.CloudBuild.V1 version 2.6.0 (#10776)

Changes in this release:

### New features

- Add update_mask to UpdateBuildTriggerRequest proto ([commit 1b10e84](https://togithub.com/googleapis/google-cloud-dotnet/commit/1b10e842187af385bf22f2ab334785539c72a0c3))
- Add automap_substitutions flag to use substitutions as envs in Cloud Build ([commit ae515fb](https://togithub.com/googleapis/google-cloud-dotnet/commit/ae515fb363445ea21c06500acce5d53a08d34081))
- Add git_file_source and git_repo_source to build_trigger ([commit 510e913](https://togithub.com/googleapis/google-cloud-dotnet/commit/510e9133c70a36d731b563d10225d5238422be75))

apis/Google.Cloud.CloudBuild.V1/Google.Cloud.CloudBuild.V1/Google.Cloud.CloudBuild.V1.csproj

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <Version>2.5.0</Version>
+    <Version>2.6.0</Version>
     <TargetFrameworks>netstandard2.1;net462</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <Description>Recommended Google client library to access the Google Cloud Build API v1, which creates and manages builds on Google Cloud Platform.</Description>

apis/Google.Cloud.CloudBuild.V1/docs/history.md

@@ -1,5 +1,13 @@
 # Version history
 
+## Version 2.6.0, released 2023-08-04
+
+### New features
+
+- Add update_mask to UpdateBuildTriggerRequest proto ([commit 1b10e84](https://github.com/googleapis/google-cloud-dotnet/commit/1b10e842187af385bf22f2ab334785539c72a0c3))
+- Add automap_substitutions flag to use substitutions as envs in Cloud Build ([commit ae515fb](https://github.com/googleapis/google-cloud-dotnet/commit/ae515fb363445ea21c06500acce5d53a08d34081))
+- Add git_file_source and git_repo_source to build_trigger ([commit 510e913](https://github.com/googleapis/google-cloud-dotnet/commit/510e9133c70a36d731b563d10225d5238422be75))
+
 ## Version 2.5.0, released 2023-07-13
 
 ### New features

apis/apis.json

@@ -1168,7 +1168,7 @@
     },
     {
       "id": "Google.Cloud.CloudBuild.V1",
-      "version": "2.5.0",
+      "version": "2.6.0",
       "type": "grpc",
       "productName": "Cloud Build",
       "productUrl": "https://cloud.google.com/cloud-build",