Update OpenTelemetry compatibility matrix table (#50)

* Update OpenTelemetry compatibility matrix table * Add note about sending telemetry directly to ddagent

Author: ryanuber

website/docs/cloud-docs/agents/telemetry.mdx

@@ -58,7 +58,8 @@ version constraints become known.
 
 | Terraform Cloud Agent version | Compatible OpenTelemetry Collector version |
 | ----------------------------- | ------------------------------------------ |
-| All versions | <= 0.42.0 |
+| >= 0.1.12, <= 1.7.0 | <= 0.42.0 |
+| >= 1.7.1 | Tested up to 0.73.0 |
 
 ### Running the collector
 
@@ -93,6 +94,18 @@ docker run \
 
 The collector should start with your modified configuration.
 
+## DataDog Agent
+
+The Terraform Cloud Agent may target a DataDog agent directly instead of an
+OpenTelemetry collector. To configure the DataDog agent to accept OTLP
+connections, refer to the [DataDog OpenTelemetry
+documentation](https://docs.datadoghq.com/opentelemetry/otlp_ingest_in_the_agent).
+Note that the tfc-agent talks to a gRPC OTLP receiver only. Be sure to
+configure the DataDog agent to accept a gRPC OTLP connection. Once the
+DataDog agent is listening for gRPC connections, [configure the tfc-agent] using
+the address of the DataDog agent's gRPC listener in place of the OpenTelemetry
+collector address.
+
 ## Tracing
 
 The agent emits tracing spans which are useful in understanding and debugging