Document and automate new release process

[alamb]

Re #292

This PR contains documentation and scripts for the arrow-rs release process. It will probably evolve as we do this a few more times.

Rationale for this change

Make release process simple and repeatable

What changes are included in this PR?

1. Comprehensive documentation
2. Scripts to automate the various steps

Are there any user-facing changes?

Not directly

[codecov-commenter]

Codecov Report

Merging #299 (a59cd52) into master (c863a2c) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #299      +/-   ##
==========================================
- Coverage   82.52%   82.52%   -0.01%     
==========================================
  Files         162      162              
  Lines       44007    44007              
==========================================
- Hits        36316    36315       -1     
- Misses       7691     7692       +1     

Impacted Files	Coverage Δ
parquet/src/encodings/encoding.rs	94.85% <0.00%> (-0.20%)	⬇️

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[jorgecarleitao]

LG so far. Thanks a lot, @alamb !

[jorgecarleitao]

cc @kszucs

[alamb]

This is ready for review at your convenience @jorgecarleitao / @andygrove

[andygrove]

This doesn't work unfortunately. We have to manually go to each crate directory and run cargo publish for each one, in order.

[alamb]

Thanks -- I added the following (and I will test / update the docs again after I try with the next arrow release)

(cd arrow && cargo publish)
(cd arrow_flight && cargo publish)
(cd parquet && cargo publish)
(cd parquet_derive && cargo publish)

[andygrove]

I think we can remove this section now. This was here because we had issues with the scripts updating the version numbers early on. We should check that the version numbers are correct when voting on a release candidate.

[alamb]

will remove

[alamb]

I plan to merge this PR in and then iterate on the docs and scripts as we do some more releases. I am happy to make any other changes as part of a subsequent PR