[windows installer script] Mark Fluentd support as deprecated (#6362)

* [windows installer script] Mark Fluentd support as deprecated

* add PR number to changelog

Author: crobert-1

CHANGELOG.md

@@ -21,6 +21,8 @@ and the [opentelemetry-collector-contrib v0.128.0](https://github.com/open-telem
 
 ### 🚩 Deprecations 🚩
 
+- (Splunk) `Windows installer script`: Fluentd support has been deprecated and will be removed in a future release. ([#6362](https://github.com/signalfx/splunk-otel-collector/pull/6362))
+  Please refer to [deprecation documentation](https://github.com/signalfx/splunk-otel-collector/blob/main/docs/deprecations/fluentd-support.md) for more information.
 - (Contrib) `receiver/hostmetrics`: Mark `hostmetrics.process.onWindowsUseNewGetProcesses` feature gate as stable ([#32947](https://github.com/open-telemetry/opentelemetry-collector-contrib/pull/32947)
 
 ### 💡 Enhancements 💡

packaging/installer/install.ps1

@@ -61,6 +61,7 @@
     .EXAMPLE
     .\install.ps1 -access_token "ACCESSTOKEN" -hec_token "HECTOKEN"
 .PARAMETER with_fluentd
+    DEPRECATED: Fluentd support has been deprecated and will be removed in a future release. Please refer to documentation for more information: https://github.com/signalfx/splunk-otel-collector/blob/main/docs/deprecations/fluentd-support.md
     (OPTIONAL) Whether to install and configure fluentd to forward log events to the collector (default: $false)
     .EXAMPLE
     .\install.ps1 -access_token "ACCESSTOKEN" -with_fluentd $true
@@ -683,6 +684,7 @@ following PowerShell commands:
 echo "$message"
 
 if ($with_fluentd) {
+    Write-Warning '[DEPRECATED] Fluentd support has been deprecated and will be removed in a future release. Please refer to documentation for more information: https://github.com/signalfx/splunk-otel-collector/blob/main/docs/deprecations/fluentd-support.md'
     $default_fluentd_config = "$installation_path\fluentd\td-agent.conf"
     $default_confd_dir = "$installation_path\fluentd\conf.d"