Merge pull request #186 from JohanMabille/upgrade_xtensor

Upgraded to xtensor 0.27.1

Author: JohanMabille

environment-dev.yml

@@ -16,4 +16,4 @@ dependencies:
   - nlohmann_json
   - google-cloud-cpp >=3.0,<4
   - aws-sdk-cpp >=1.11,<2
-  - xtensor=0.26.0
+  - xtensor=0.27.1