Fixed rss.xml to include post author info.
Fixed rss.xml to include post author info.

Signed-off-by: Mikael Zulfigarov <1fcb9933191574c0a92118d08f2b049f180dc230@sysgears.com>

sysgears/grain-theme-clean-blog,sysgears/grain-theme-clean-blog,sysgears/grain-theme-clean-blog,sysgears/grain-theme-clean-blog,sysgears/grain-theme-clean-blog