Oscar.jl 0.4.0 released

Today Oscar.jl 0.4.0 has been released.

Diff since v0.3.0

Closed issues:

• Error while compiling Oscar v0.2.0 with Xcode >= 11.4 (#82)
• Oscar.build() fails with Oscar 0.3.0 due to a GMP issue with GAP.jl v0.3.5 (#99)
• Oscar tests crash on Julia 1.4.2 on Ubuntu (#104)

Merged pull requests:

• import GAPGroups (#84) (@GDeFranceschi)
• More work on groups stuff, for Oscar demo (#102) (@fingolfin)
• Fix typos in ?Oscar help (#103) (@wbhart)
• Primary Decomposition via GTZ. (#105) (@raulepure)
• Fixed typo in Primary Decomposition Code (#106) (@raulepure)
• Some work on groups (#107) (@fingolfin)
• Work around compiler bug (#110) (@thofma)
• groups: interface to various GAP group libraries (#113) (@fingolfin)
• Groups: a few small suggestions (#114) (@ThomasBreuer)
• Travis: fix building & deploying the manual (#115) (@fingolfin)
• Update authors list (#117) (@fingolfin)