lib/time: update tzdata before release

[tklauser]

The timezone database in lib/time should be updated shortly before the 1.10 release (to whatever tzdata release is current then). There was https://golang.org/cl/74230 attempting to do this just now, but it was too early. @ALTree suggested to open an issue about this, so we don't forget.

The latest available version is shown at https://www.iana.org/time-zones.

[gopherbot]

Change https://golang.org/cl/74230 mentions this issue: lib/time: update tzdata to 2017c

[bradfitz]

2017c is still the latest. Will regarget to Go 1.11.

[ksshannon]

2018a came out a few days ago:

https://www.iana.org/time-zones

I'm assuming it's too late in the cycle, but just thought I'd post.

[ALTree]

That's weird, they didn't even announce it in the mailing list: http://mm.icann.org/pipermail/tz-announce/

Anyway I've looked at the CHANGELOG and there are a few changes in the timezones data, here's the short version:

Release 2018a

  - São Tomé and Príncipe switched from +00 to +01.
  - Brazil's DST will now start on November's first Sunday.
  - Ireland's standard time is now in the summer, not the winter.

We could try to update it and see if anything breaks (usually it's the tests). If everything is fine, maybe it could be shipped with go1.10

[ALTree]

At the moment our update script is broken because the 2018a release is not yet published at https://data.iana.org/time-zones/releases/, which is the place we visit to download the data. Considering this (and the fact that the new release wasn't even announced in the tz-announce mailing list) we should probably wait.

[ksshannon]

Agreed, I've downloaded the archives and make fails, so I think it may have issues.

[ksshannon]

There was an issue with the archive, 2018b will be released in a few days:

http://mm.icann.org/pipermail/tz/2018-January/025814.html

[ksshannon]

Another issue with 2018b, but 2018c finally made it to the announce list:

http://mm.icann.org/pipermail/tz-announce/2018-January/000048.html