Updating CHANGELOG for 1.8.2rc1

Adding .readthedocs.yml

fix timeout issues with readthedocs

[AIRFLOW-1201] Update deprecated 'nose-parameterized'

The 'parameterized' package should be used now,

Closes apache#2298 from skudriashev/airflow-1201

Merge branch 'v1-8-stable' of https://git-wip-us.apache.org/repos/asf…

…/incubator-airflow into v1-8-stable

1.8.0 Release

Also tag 1.8.0+apache.incubating

Adding .readthedocs.yml to build docs for 1.7.1.3

Adding .readthedocs.yml to build versioned docs

Merge pull request apache#3 from airbnb/plypaul_disable_run_connectio…

…n_pool

Disable connection pool for `airflow run` commands