Update vcs-agent-pools.md to add azure_devops

add azure_devops to vcs agent pools ref from github repository https://github.com/spacelift-io/vcs-agent?tab=readme-ov-file#configuration

docs/concepts/vcs-agent-pools.md

@@ -69,7 +69,7 @@ A number of configuration variables is available to customize how your VCS Agent
 | ------------------------ | ------------------------------------------ | -------- | ------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
 | `--target-base-endpoint` | `SPACELIFT_VCS_AGENT_TARGET_BASE_ENDPOINT` | Required |               | The internal endpoint of your VCS system, including the protocol, as well as port, if applicable. (e.g., `http://169.254.0.10:7990`) |
 | `--token`                | `SPACELIFT_VCS_AGENT_POOL_TOKEN`           | Required |               | The token you’ve received from Spacelift during VCS Agent Pool creation                                                              |
-| `--vendor`               | `SPACELIFT_VCS_AGENT_VENDOR`               | Required |               | The vendor of your VCS system. Currently available options are `gitlab`, `bitbucket_datacenter` and `github_enterprise`              |
+| `--vendor`               | `SPACELIFT_VCS_AGENT_VENDOR`               | Required |               | The vendor of your VCS system. Currently available options are `azure_devops`, `gitlab`, `bitbucket_datacenter` and `github_enterprise`              |
 | `--allowed-projects`     | `SPACELIFT_VCS_AGENT_ALLOWED_PROJECTS`     | Optional | `.*`          | Regexp matching allowed projects for API calls. Projects are in the form: 'group/repository'.                                        |
 | `--bugsnag-api-key`      | `SPACELIFT_VCS_AGENT_BUGSNAG_API_KEY`      | Optional |               | Override the Bugsnag API key used for error reporting.                                                                               |
 | `--parallelism`          | `SPACELIFT_VCS_AGENT_PARALLELISM`          | Optional | `4`           | Number of streams to create. Each stream can handle one request simultaneously.                                                      |