Error: Failed to install 'grattan' from GitHub: (converted from warning) unable to access index for repository https://hughparsonage.github.io/tax-drat/bin/macosx/el-capitan/contrib/3.6: cannot open URL 'https://hughparsonage.github.io/tax-drat/bin/macosx/el-capitan/contrib/3.6/PACKAGES'
remotes::install_github("hughparsonage/grattan", dependencies = TRUE)
fails with error:
Error: Failed to install 'grattan' from GitHub: (converted from warning) unable to access index for repository https://hughparsonage.github.io/tax-drat/bin/macosx/el-capitan/contrib/3.6: cannot open URL 'https://hughparsonage.github.io/tax-drat/bin/macosx/el-capitan/contrib/3.6/PACKAGES'