Did you trim some of that error message? It's likely there was some other output that could be useful in diagnosing the error.
Regardless, this is most likely because renv is attempting to install dplyr from sources (rather than using an RSPM binary), and unfortunately the virtual machines used on RStudio Cloud do not have enough RAM in order to be able to compile packages from source.
It would also be helpful to know what repositories are encoded in renv.lock, since it's possible that your lockfile is requesting the use of CRAN rather than the repository normally used by RSPM .