Fix typo 👇🏻
Fix typo 👇🏻

https://github.com/poteto/hiring-without-whiteboards/blob/master/README.md#L190: corrected "flavours" to "flavors"
https://github.com/poteto/hiring-without-whiteboards/blob/master/README.md#L324: corrected "excercise" to "exercise"
https://github.com/poteto/hiring-without-whiteboards/blob/master/README.md#L423: corrected "Magnetis" to "Magnets"
https://github.com/poteto/hiring-without-whiteboards/blob/master/README.md#L490: corrected "excercise" to "exercise"
https://github.com/poteto/hiring-without-whiteboards/blob/master/README.md#L550: corrected "Occassionally" to "Occasionally"
https://github.com/poteto/hiring-without-whiteboards/blob/master/README.md#L561: corrected "ocassionally" to "occasionally"
https://github.com/poteto/hiring-without-whiteboards/blob/master/README.md#L589: corrected "challanges" to "challenges"
https://github.com/poteto/hiring-without-whiteboards/blob/master/README.md#L589: corrected "neccessary" to "necessary"
https://github.com/poteto/hiring-without-whiteboards/blob/master/README.md#L680: corrected "excercise" to "exercise"

poteto/hiring-without-whiteboards