ext/datadog: Fix API/SDK dependencies in datadog exporter (open-telemetry#859)

Author: mariojonke

Diff for: ext/opentelemetry-ext-datadog/setup.cfg

@@ -40,8 +40,8 @@ package_dir=
 packages=find_namespace:
 install_requires =
     ddtrace>=0.34.0
-    opentelemetry-api==0.10.dev0
-    opentelemetry-sdk==0.10.dev0
+    opentelemetry-api==0.11.dev0
+    opentelemetry-sdk==0.11.dev0
 
 [options.packages.find]
 where = src