Bump go.opentelemetry.io/otel/sdk in /examples/demo/app (#2283)

Bumps [go.opentelemetry.io/otel/sdk](https://github.com/open-telemetry/opentelemetry-go) from 0.14.0 to 0.15.0.
- [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@v0.14.0...v0.15.0)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

examples/demo/app/go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/kr/pretty v0.1.0 // indirect
 	go.opentelemetry.io/otel v0.15.0
 	go.opentelemetry.io/otel/exporters/otlp v0.14.0
-	go.opentelemetry.io/otel/sdk v0.14.0
+	go.opentelemetry.io/otel/sdk v0.15.0
 	golang.org/x/net v0.0.0-20200625001655-4c5254603344 // indirect
 	golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211 // indirect
 	golang.org/x/text v0.3.3 // indirect

examples/demo/app/go.sum

@@ -66,6 +66,8 @@ go.opentelemetry.io/otel/exporters/otlp v0.14.0 h1:B5uCGwaThlJMVpCeOxRkiVeOhT2t0
 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=
 go.opentelemetry.io/otel/sdk v0.14.0/go.mod h1:kGO5pEMSNqSJppHAm8b73zztLxB5fgDQnD56/dl5xqE=
+go.opentelemetry.io/otel/sdk v0.15.0 h1:Hf2dl1Ad9Hn03qjcAuAq51GP5Pv1SV5puIkS2nRhdd8=
+go.opentelemetry.io/otel/sdk v0.15.0/go.mod h1:Qudkwgq81OcA9GYVlbyZ62wkLieeS1eWxIL0ufxgwoc=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=