1.0.1 patch release status

[Krisztián Szűcs <sz...@gmail.com>]

Hi,

It took me a couple of attempts to cherry pick the selected jira
issues' patches to the maint-1.0.x maintenance branch although I had
to exclude a couple of patches, namely:
- https://issues.apache.org/jira/browse/ARROW-9716
- https://issues.apache.org/jira/browse/ARROW-9714
- https://issues.apache.org/jira/browse/ARROW-9672

The first two tickets were depending on backward incompatible
improvement patches which were not part of 1.0.0 release, so they
caused a fair amount of conflicts during the cherry pick process.
The third patch doesn't have a patch yet and it is mostly about an API change.

Please be careful when selecting tickets for patch releases and also:
- include tickets that the bug fix depends on
- watch out for backward incompatible changes because we have moved to
semantic versioning.

I also executed the curation script which highlighted that there are
33 patches applied on the maintenance branch but the jira release
contains only 31 tickets. It turned out that there are patches with
the same issue numbers:
- https://github.com/apache/arrow/pull/7867 and
https://github.com/apache/arrow/pull/7893
- https://github.com/apache/arrow/pull/7892 and
https://github.com/apache/arrow/pull/7894

While the patches are indeed related to the same issues, it would be
better to have unique issue numbers for all patches landing on master
and reference the ticket relationship using the jira issue linking.

I'm executing the CI builds (including packaging tasks) on the maint
branch. If everything works well, I'm going to cut 1.0.1-RC0
afterwards.

Thanks, Krisztian