README update for multiprocess deprecation

[hdblcr]

When running get_logs using the recommendations on README, below, I get a warning.

README Recommendations

library(future)
plan(multiprocess)

Warning Message

Warning: Strategy 'multiprocess' is deprecated in future (>= 1.20.0). Instead, explicitly specify either 'multisession' or 'multicore'. In the current R session, 'multiprocess' equals 'multisession'.

Please update the README recommendations to indicate whether to use multisession (probably) or multicore.

Thanks for the great package!