README: link to Slack and Discord via cuelang.org
This updates the README to use platform-specific redirectors created on
cuelang.org (in https://cuelang.org/cl/1196779) that single-source the
unwieldy links that the platforms require.
Also: update code of conduct link to the correct cuelang.org URL.
Signed-off-by: Jonathan Matthews <github@hello.jonathanmatthews.com>
Change-Id: I4bd686700c9b2dddb2332de40b880ddf8d5e8b36
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1196782
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
authored by