Singular.jl 0.5.0 released

Today Singular.jl 0.5.0 has been released.

Diff since v0.4.7

Merged pull requests:

• add special case for N_GField(p, 1) (#391) (@tthsqe12)
• Deprecate coeffs (#393) (@wbhart)
• proper expressify for n_transExt (#394) (@tthsqe12)
• Bump version to 0.5.0 (#396) (@thofma)