Added support for arm64.

[joeledwards]

I added support for the arm64 architecture.

This is already made available on nodejs.org. In the archives it is identified as arm64. I have seen it identified on systems as both arm64 and aarch64, so both are mapped to arm64 in my update.

[tlvince]

@troy0820 / other contributors, sorry for the +1 comment, but could this get merged in? It's nearly a year old, but will merge cleanly and is very useful for ARM machines. See also #494 and #507. Thanks!

[shadowspawn]

For reference, question and explanation why both arm64 and aarch64
https://stackoverflow.com/questions/31851611/differences-between-arm64-and-aarch64

[shadowspawn]

Looks good to me. (I am not a maintainer.)

[farmio]

Worked for me.

[MichaIng]

Simple, clean and jep required on ARMv8 systems to run n without adding explicit -a option. Currently it attempts to install the amd64 version otherwise, which of course fails.

Please merge this to avoid further user reports/complains.

[shadowspawn]

(If a fork of n is an option to readers with this problem, I added aarch64 and arm64 support to https://github.com/shadowspawn/nvh prompted by this issue, and willing to make changes if not working as intended. Note: nvh requires rsync.)

[shadowspawn]

Aiming to have this released within a week. Manually merged into develop branch preparing for release. See #559

[shadowspawn]

Released in v3.0.0