Bump google-api-core package version to make apache-airflow-providers-google compatible with python3.6

Apache Airflow version: 1.10.14 and 1.10.15

Environment Official Docker image python 3.6

What happened:

The backport package apache-airflow-backport-providers-google has a dependency on google-api-core:

• apache-airflow-backport-providers-google — >=1.25.1,<2.0.0
• airflow 1.10.14 constraints for python 3.6 — google-api-core==1.23.0

Those two do not overlap in any version. Setting google-api-core==1.26.3 will make it solve the dependencies again

What you expected to happen:

Should be posible to install airflow with the current constraints.

pip install apache-airflow-backport-providers-google -c https://raw.githubusercontent.com/apache/airflow/constraints-1.10.14/constraints-3.6.txt 

[potiuk]

@dinigo. Everything is as expected.

Constraints are frozen at the time of creating the apache-airflow package. And they are there to be able to install the given version of apache-airflow in a consistent way. No more, no less. They have nothing to do with the version of provider that you can install afterwards. Constraints finish their role when you have apache-airflow installed, and then you should manage your additional packages (including backport providers) on your own.

There is (and cannot be) absolutely no relation of the constraints with version 1.10.14 to the providers/backport providers (which are released on a completely dfferent schedule).

You should not use constraints to install providers/backports, this is neither endorsed not supported. You should install providers (or backport providers) separately, without constraints.

[uranusjr]

The constraint files are automatically generated from CI, and you shouldn’t be modifying them directly.

I believe the way to do it is to change the minimal version in setup.py; CI will pick them up automatically and update the constraints files accordingly.