Bump go.opentelemetry.io/otel in /examples/demo/app

Bumps [go.opentelemetry.io/otel](https://github.com/open-telemetry/opentelemetry-go) from 0.15.0 to 0.16.0.
- [Release notes](https://github.com/open-telemetry/opentelemetry-go/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-go/blob/master/CHANGELOG.md)
- [Commits](open-telemetry/opentelemetry-go@v0.15.0...v0.16.0)

Signed-off-by: dependabot[bot] <support@github.com>

examples/demo/app/go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/golang/protobuf v1.4.3 // indirect
 	github.com/kr/pretty v0.1.0 // indirect
-	go.opentelemetry.io/otel v0.15.0
+	go.opentelemetry.io/otel v0.16.0
 	go.opentelemetry.io/otel/exporters/otlp v0.14.0
 	go.opentelemetry.io/otel/sdk v0.15.0
 	golang.org/x/net v0.0.0-20200625001655-4c5254603344 // indirect

examples/demo/app/go.sum

@@ -62,6 +62,8 @@ go.opentelemetry.io/otel v0.14.0 h1:YFBEfjCk9MTjaytCNSUkp9Q8lF7QJezA06T71FbQxLQ=
 go.opentelemetry.io/otel v0.14.0/go.mod h1:vH5xEuwy7Rts0GNtsCW3HYQoZDY+OmBJ6t1bFGGlxgw=
 go.opentelemetry.io/otel v0.15.0 h1:CZFy2lPhxd4HlhZnYK8gRyDotksO3Ip9rBweY1vVYJw=
 go.opentelemetry.io/otel v0.15.0/go.mod h1:e4GKElweB8W2gWUqbghw0B8t5MCTccc9212eNHnOHwA=
+go.opentelemetry.io/otel v0.16.0 h1:uIWEbdeb4vpKPGITLsRVUS44L5oDbDUCZxn8lkxhmgw=
+go.opentelemetry.io/otel v0.16.0/go.mod h1:e4GKElweB8W2gWUqbghw0B8t5MCTccc9212eNHnOHwA=
 go.opentelemetry.io/otel/exporters/otlp v0.14.0 h1:B5uCGwaThlJMVpCeOxRkiVeOhT2t0GcZp8G+x219W5k=
 go.opentelemetry.io/otel/exporters/otlp v0.14.0/go.mod h1:DmFebmd697PT2nIQ6t6p1tx9KQFu+R2PGd+3W62OkAE=
 go.opentelemetry.io/otel/sdk v0.14.0 h1:Pqgd85y5XhyvHQlOxkKW+FD4DAX7AoeaNIDKC2VhfHQ=