v0.6.0

QuadraticModels v0.6.0

Diff since v0.5.0

Merged pull requests:

• [AUTO] Change master to main (#47) (@abelsiqueira)
• [AUTO] Fix docs to use main (#48) (@abelsiqueira)
• Presolve fixed variables (#49) (@geoffroyleconte)
• sort cols (#51) (@geoffroyleconte)
• Version 0.6 (#52) (@geoffroyleconte)