Release v0.2.0

[Maximilian-Stefan-Ernst]

• CI fails mysteriously from time to time #117
• Typo in Chapter "Model Construction" (change "oder" to "or" in second sentence) #114
• What types of models do not need an imply? #108
• Sorting of ensemble models #67
• export optimizer field access method #130
• update to julia 1.9 #139
• TagBot file does not have an extension #132