opentelemetry-go's Schema ParseFile leaks file descriptors on each parse

Summary go.opentelemetry.io/otel/schema/v1.0 and go.opentelemetry.io/otel/schema/v1.1 leaks one file descriptor on each successful ParseFile call. ParseFile opens the schema file and passes it to Parse without closing it; repeated parsing in a long-running process can exhaust the process file...