Some of the in game credits have it listed as so:

Unshaken
D'Angelo
Written by Daniel Landis, Rocco DeLuca and Michael Eugene Archer
Published by Daniel Landis Songs (ASCAP)
Administered by Penny Farthing Music, c/o Concord Music Publishing; Aunt Dolly Music (BMI); Universal Polygram Publishing Inc. o/b/o Ah Choo Music Publishing (ASCAP)
D'Angelo - Electric Piano/Vocals
Daniel Landis - Guitar
Brian Blade - Drums
Cyril Neville - Percussion
Daryl Johnson - Percussion
D'Angelo appears courtesy of RCA Records
Courtesy of Rockstar Games Inc.

Also, it looks like Daniel Landis did a slew of songs for the game, including one by performed by Rhiannon Giddens (Who at one time was with the Carolina Chocolate Drops group) titled "Moonlight Open Hymn".