Combine changelog entires for AIPs 39 and 40 in to a single row (#18633)
Combine changelog entires for AIPs 39 and 40 in to a single row (#18633)

We had a number of PRs for both of these AIPs, including a few "bug fix"
ones that don't really make sense on their own as they are part of a new
feature.

I have changed it to combine all of the PRs that are part of these AIPs
in to one line each.

I also removed a few duplicated entries, or ones that are only touching
providers.
apache/airflow,Acehaidrey/incubator-airflow,nathanielvarona/airflow,bolkedebruin/airflow,danielvdende/incubator-airflow,lyft/incubator-airflow,apache/airflow,apache/airflow,Acehaidrey/incubator-airflow,cfei18/incubator-airflow,apache/incubator-airflow,nathanielvarona/airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,mistercrunch/airflow,danielvdende/incubator-airflow,bolkedebruin/airflow,lyft/incubator-airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,apache/incubator-airflow,lyft/incubator-airflow,nathanielvarona/airflow,bolkedebruin/airflow,danielvdende/incubator-airflow,mistercrunch/airflow,mistercrunch/airflow,danielvdende/incubator-airflow,apache/airflow,nathanielvarona/airflow,apache/incubator-airflow,cfei18/incubator-airflow,bolkedebruin/airflow,nathanielvarona/airflow,lyft/incubator-airflow,nathanielvarona/airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,apache/airflow,apache/airflow,mistercrunch/airflow,cfei18/incubator-airflow,bolkedebruin/airflow,apache/incubator-airflow,Acehaidrey/incubator-airflow