update for pelican 4

[nim65s]

Hi,

According to pelican's doc:

If upgrading from 3.7.x or earlier, please note that slug-related settings in 4.0+ use {slug} and/or {lang} rather than %s. If %s-style settings are encountered, Pelican will emit a warning and fall back to the default setting. Some user-submitted themes might try to format setting values but fail upon site build with a TypeError. In such cases, the theme needs to be updated. For example, instead of TAG_FEED_ATOM|format(tag.slug), use TAG_FEED_ATOM|format(slug=tag.slug)

This PR fixed build in my case.

[amorphic]

Would be great to get this merged. I just updated my blog to use Attila with Pelican 4 and came across this same issue.

[arulrajnet]

Thanks for the PR. Will review today.

…

On Wed, Jan 2, 2019, 7:15 PM James Stewart ***@***.*** wrote: Would be great to get this merged. I just updated my blog to use Attila with Pelican 4 and came across this same issue. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#40 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAy74Qwff0APMXHyplZJKT-j7hkSIUQ8ks5u_LgDgaJpZM4ZdHGb> .

[arulrajnet]

Updated the demo site with the fix http://attila.demo.arulraj.net/tag/general/