Update opentelemetry-go monorepo

| datasource | package                                 | from    | to      |
| ---------- | --------------------------------------- | ------- | ------- |
| go         | go.opentelemetry.io/otel                | v0.17.0 | v0.20.0 |
| go         | go.opentelemetry.io/otel/exporters/otlp | v0.17.0 | v0.20.1 |
| go         | go.opentelemetry.io/otel/sdk            | v0.17.0 | v0.20.0 |
| go         | go.opentelemetry.io/otel/trace          | v0.17.0 | v0.20.0 |


Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

example/go/otel/go.mod

@@ -5,8 +5,8 @@ go 1.16
 require (
 	github.com/pkg/errors v0.9.1
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.17.0
-	go.opentelemetry.io/otel v0.17.0
-	go.opentelemetry.io/otel/exporters/otlp v0.17.0
-	go.opentelemetry.io/otel/sdk v0.17.0
-	go.opentelemetry.io/otel/trace v0.17.0
+	go.opentelemetry.io/otel v0.20.0
+	go.opentelemetry.io/otel/exporters/otlp v0.20.1
+	go.opentelemetry.io/otel/sdk v0.20.0
+	go.opentelemetry.io/otel/trace v0.20.0
 )