GLM v1.4.2

Diff since v1.4.1

Closed issues:

• unexplained SingularException (#43)
• Syntax of the weight option (#106)
• Consistency w.r.t. external weights (#124)
• DomainError with LogLink (#129)
• Exception for failure to converge? (#163)
• Export fewer functions? (#168)
• lm doesn't support wts (#258)
• Error Handling (#279)
• Why must binomial response be 0 < y < 1 (#291)
• GEE (#399)
• Cooks distance (#414)

Merged pull requests:

• Fix tests on Julia 1.6 (#416) (@nalimilan)
• bump DataFrames.jl to 1.0 and version to 1.4.2 (#421) (@bkamins)