Use OTEL collector image from GHCR (open-telemetry#732)

Signed-off-by: Pavol Loffay <p.loffay@gmail.com>

main.go

@@ -85,7 +85,7 @@ func main() {
 	pflag.BoolVar(&enableLeaderElection, "enable-leader-election", false,
 		"Enable leader election for controller manager. "+
 			"Enabling this will ensure there is only one active controller manager.")
-	pflag.StringVar(&collectorImage, "collector-image", fmt.Sprintf("otel/opentelemetry-collector:%s", v.OpenTelemetryCollector), "The default OpenTelemetry collector image. This image is used when no image is specified in the CustomResource.")
+	pflag.StringVar(&collectorImage, "collector-image", fmt.Sprintf("ghcr.io/open-telemetry/opentelemetry-collector-releases/opentelemetry-collector:%s", v.OpenTelemetryCollector), "The default OpenTelemetry collector image. This image is used when no image is specified in the CustomResource.")
 	pflag.StringVar(&targetAllocatorImage, "target-allocator-image", fmt.Sprintf("ghcr.io/open-telemetry/opentelemetry-operator/target-allocator:%s", v.TargetAllocator), "The default OpenTelemetry target allocator image. This image is used when no image is specified in the CustomResource.")
 	pflag.StringVar(&autoInstrumentationJava, "auto-instrumentation-java-image", fmt.Sprintf("ghcr.io/open-telemetry/opentelemetry-operator/autoinstrumentation-java:%s", v.AutoInstrumentationJava), "The default OpenTelemetry Java instrumentation image. This image is used when no image is specified in the CustomResource.")
 	pflag.StringVar(&autoInstrumentationNodeJS, "auto-instrumentation-nodejs-image", fmt.Sprintf("ghcr.io/open-telemetry/opentelemetry-operator/autoinstrumentation-nodejs:%s", v.AutoInstrumentationNodeJS), "The default OpenTelemetry NodeJS instrumentation image. This image is used when no image is specified in the CustomResource.")