Oscar.jl 0.3.0 released

Today Oscar.jl 0.3.0 has been released.

Diff since v0.2.0

Closed issues:

• release 0.1.1 (#76)
• Setup Travis and Code coverage tracking (#86)

Merged pull requests:

• Update README.md (#85) (@fingolfin)
• Update Travis settings, add Travis & Codecov badges to README.md (#87) (@fingolfin)
• Setup Travis and Code coverage tracking in README.md (#88) (@mohamed-barakat)
• Add CompatHelper action (#91) (@fingolfin)
• Update to latest Polymake.jl, Singular.jl (#93) (@fingolfin)
• Version 0.3.0 (#96) (@fingolfin)