e3.js

let books = [
    {
        pages: 200,
        year: 2020,
        author: {
            firstName: "Paul",
            lastName: "Anton"
        },
        language: "DE"    
    },
    {
        pages: 230,
        year: 2020,
        author: {
            firstName: "Oliver",
            lastName: "G"
        },
        format: "DE"    
    },
]


// E3
// 3.1 Write a function that increases the year of all books by 1 (optional: arrow function)
// 3.2 Convert all author's first names to lowercase
// 3.3 Convert all author's last names to uppercase