Updates Jackson usage to use immutable ObjectReader/Writer instead of ObjectMapper

[bdemers]

… ObjectMapper

Jackson 2.10+ recommend using ObjectReader and ObjectWriter as opposed to ObjectMapper https://cowtowncoder.medium.com/jackson-3-0-immutability-w-builders-d9c532860d88

[coveralls]

Coverage remained the same at 100.0% when pulling 0c55bfce677366a8d0a17e690c6822abb90ff878 on jackson-immutable into 9007ae7c98f04ea16b987a8a4b0eb7779a34dad0 on master.

[lhazlewood]

@bdemers do you want to rebase?