Faces in more places!
If you link github directly to your Google+ profile it's a little easier.
Originally shared by Malte Ubl
Getting author annotations for your Github projects in Google search
See, there is my face next to my Github project :)
How did I do it:
My Github projects has www.nonblocking.io listed as my website. That website has this bit of markup:
<a href='' rel='me'>Malte Ubl @ Github
So it says that both my G+ profile and my Github profile are both "me".
Now my G+ profile links to www.nonblocking.io as well (and actually to my Github profile). Those 3 things together establish a pretty safe link between my Google profile and my Github profile and Google starts to surface the association in search. Neat
PS: Only because I work for Google, absolutely positive does not imply that I know what I'm doing, so your experience may vary.