Bump version to 3.1.2
Bump version to 3.1.2

We only fixed a deprecation warning, we didn't change anything, so this
only calls for a patch version bump.

Co-authored-by: Aaron Hill <4e0f0ffd7e46d29f2d6b4c0cdeb34f142e25b7de@gmail.com>
Co-authored-by: Alex Stone <a0b2b61e2edcf99aa16080c2254a6ae6923d1fac@radiusnetworks.com>
Co-authored-by: Corrie Leech <7fc8c7191441df1401809be042fb216d2cf950b6@gmail.com>
Co-authored-by: JC Avena <c7fdf04413e5bbdb005bd636b0202f683c7b1bbf@gmail.com>

RadiusNetworks/radius-rails,RadiusNetworks/radius-rails,RadiusNetworks/radius-rails,RadiusNetworks/radius-rails,RadiusNetworks/radius-rails