Fix dead link (#7575)

docs/en/setup/backend/backend-receivers.md

@@ -110,7 +110,7 @@ E.g. The `oc` handler loads rules from `$CLASSPATH/otel-oc-rules`.
 
 Supported handlers:
 
-* `oc`: [OpenCensus](https://github.com/open-telemetry/opentelemetry-collector/blob/master/exporter/opencensusexporter/README.md) gRPC service handler.
+* `oc`: [OpenCensus](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/a08903f05d3a544f548535c222b1c205b9f5a154/exporter/opencensusexporter/README.md) gRPC service handler.
 
 **Notice:**  Set `SW_OTEL_RECEIVER=default` through system environment or change `receiver-otel/selector=${SW_OTEL_RECEIVER:default}` to activate the OpenTelemetry receiver.
 

docs/en/setup/istio/README.md

@@ -39,7 +39,7 @@ relabel_configs:
   replacement: <cluster name>
 ```
 
-or opt to [Resource Processor](https://github.com/open-telemetry/opentelemetry-collector/blob/master/processor/resourceprocessor/README.md):
+or opt to [Resource Processor](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/a08903f05d3a544f548535c222b1c205b9f5a154/processor/resourceprocessor/README.md):
 
 ```
 processors:
@@ -55,7 +55,7 @@ the issues described [here](https://github.com/open-telemetry/opentelemetry-coll
 Try to use the solution indicated in this issue if it's not fixed.
 
 #### OpenCensus exporter
-Follow [OpenCensus exporter configuration](https://github.com/open-telemetry/opentelemetry-collector/blob/master/exporter/opencensusexporter/README.md)
+Follow [OpenCensus exporter configuration](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/a08903f05d3a544f548535c222b1c205b9f5a154/exporter/opencensusexporter/README.md)
 to set up a connection between OpenTelemetry collector and OAP cluster. `endpoint` is the address of OAP gRPC service.
 
 ## Observe Istio