Singular.jl 0.21.2 released

Today Singular.jl 0.21.2 has been released.

Diff since v0.21.1

Merged pull requests:

• Adjust to upcoming Nemo finite field changes (#743) (@thofma)
• fix: improper use of broadcasting (#745) (@thofma)
• chore: new compat entries for AA and Nemo (#746) (@thofma)