Profile command sometimes returns an unknown join date

[Shadran]

Is your feature request related to a problem? Please describe.
The profile command uses RFC3339Nano to parse the date, while discord uses the ISO 8601 date format, which is similar but less restrictive.
This causes the parse to sometimes fail.

Describe the solution you'd like
Changing the time.RFC3339Nano to "2006-01-02T15:04:05-0700" should solve the problem (go has no inbuilt format for ISO 8601)

[camd67]

Interestingly, discordgo's timestamp parse uses non-nano RFC3339 to parse. I agree on using the custom string to parse it out though.

[camd67]

Turns out this wasn't due to the parsing (though I did change to the built-in discordgo parsing. Using the string described in this issue (and the stackoverflow comment) actually fails to parse out joinedAt dates in my testing. I'm thinking this was a different issue that manifested itself via the profile command but I added some more logging to test that out.

[camd67]

Reopening due to more Unknown failures in production. Checking into logs to figure out what the timestamps are and why this is happening

[camd67]

Turns out this was due to a user changing their nickname? Accurate repro steps are:

1. .moe profile -> works file
2. Change your nickname
3. .moe profile -> unknown start date
   The server returns a blank string for the timestamp
   moebot | 2018/08/24 04:28:03 Problem converting server join date to time. User ID {XXXX}, Joined at time: {} error: parsing time "" as "2006-01-02T15:04:05Z07:00": cannot parse "" as "2006"

[camd67]

After more investigation, this turned out to be a discordgo bug due to undocumented discord behavior... bwmarrin/discordgo#533 so we'll be switching to the develop branch since it's much more up to date