ARROW-6679: [RELEASE] Add license info for the autobrew scripts
ARROW-6679: [RELEASE] Add license info for the autobrew scripts

cf. https://github.com/jeroen/autobrew/blob/gh-pages/LICENCE.txt

Closes #5501 from nealrichardson/autobrew-license and squashes the following commits:

3e790f5b8 <Neal Richardson> MIT license for autobrew

Authored-by: Neal Richardson <beb59f0141269d2d04e73d0dcc1967b64ba87e13@gmail.com>
Signed-off-by: Wes McKinney <3be70eed0275ec2606f002bff3514252e145d204@apache.org>

kou/arrow,laurentgo/arrow,laurentgo/arrow,laurentgo/arrow,apache/arrow,renesugar/arrow,renesugar/arrow,wesm/arrow,cpcloud/arrow,wesm/arrow,apache/arrow,kou/arrow,xhochy/arrow,laurentgo/arrow,cpcloud/arrow,xhochy/arrow,apache/arrow,kou/arrow,apache/arrow,icexelloss/arrow,wesm/arrow,wesm/arrow,renesugar/arrow,laurentgo/arrow,renesugar/arrow,cpcloud/arrow,cpcloud/arrow,apache/arrow,apache/arrow,icexelloss/arrow,wesm/arrow,laurentgo/arrow,renesugar/arrow,wesm/arrow,kou/arrow,laurentgo/arrow,laurentgo/arrow,wesm/arrow,icexelloss/arrow,kou/arrow,apache/arrow,cpcloud/arrow,cpcloud/arrow,xhochy/arrow,icexelloss/arrow,apache/arrow,xhochy/arrow,xhochy/arrow,renesugar/arrow,cpcloud/arrow,wesm/arrow,renesugar/arrow,xhochy/arrow,apache/arrow,icexelloss/arrow,wesm/arrow,laurentgo/arrow,cpcloud/arrow,laurentgo/arrow,cpcloud/arrow,cpcloud/arrow,wesm/arrow,xhochy/arrow,laurentgo/arrow,renesugar/arrow,wesm/arrow,icexelloss/arrow,cpcloud/arrow,xhochy/arrow,wesm/arrow,renesugar/arrow,kou/arrow,laurentgo/arrow,cpcloud/arrow,kou/arrow,icexelloss/arrow,xhochy/arrow,kou/arrow,apache/arrow,cpcloud/arrow,kou/arrow,xhochy/arrow,icexelloss/arrow,icexelloss/arrow,xhochy/arrow,icexelloss/arrow,renesugar/arrow,renesugar/arrow,xhochy/arrow,kou/arrow,icexelloss/arrow,icexelloss/arrow,renesugar/arrow,cpcloud/arrow,apache/arrow,kou/arrow,kou/arrow,kou/arrow,renesugar/arrow,wesm/arrow,renesugar/arrow,apache/arrow,icexelloss/arrow,laurentgo/arrow,kou/arrow,apache/arrow,laurentgo/arrow,laurentgo/arrow,icexelloss/arrow,apache/arrow,xhochy/arrow,wesm/arrow,xhochy/arrow,xhochy/arrow,renesugar/arrow