[chore] Fix CHANGELOG.md link (#1857)

Author: jvoravong

CHANGELOG.md

@@ -138,7 +138,7 @@ This Splunk OpenTelemetry Collector for Kubernetes release adopts the [Splunk Op
 - `operator`: Migrate the operator to use Helm generated TLS certificates instead of cert-manager by default ([#1648](https://github.com/signalfx/splunk-otel-collector-chart/pull/1648))
   - Previously, certificates were generated by cert-manager by default; now they are generated by Helm templates unless configured otherwise.
   - This change simplifies the setup for new users while still supporting those who prefer using cert-manager or other solutions. For more details, see the [related documentation](https://github.com/signalfx/splunk-otel-collector-chart/tree/main/docs/auto-instrumentation-install.md#tls-certificate-requirement-for-kubernetes-operator-webhooks).
-  - If you use `.Values.operator.enabled=true` and `.Values.certmanager.enabled=true`, please review the [upgrade guidelines](https://github.com/signalfx/splunk-otel-collector-chart/blob/main/UPGRADING.md#0119-to-0120).
+  - If you use `.Values.operator.enabled=true` and `.Values.certmanager.enabled=true`, please review the [upgrade guidelines](https://github.com/signalfx/splunk-otel-collector-chart/blob/main/UPGRADING.md#01190-to-01200).
 
 ### 💡 Enhancements 💡