Improve `riskmetric` score

[AARON-CLARK]

Given the following code in scripts/riskmetric.R:

library(glue)
library(dplyr)
library(riskmetric)

assessed <- "tidyCDISC" %>%
  pkg_ref() %>%
  as_tibble() %>%
  pkg_assess()

metrics <- assessed %>%
  pkg_score() %>%
  select(-c(package, version, pkg_ref, pkg_score)) %>%
  t

riskmetric doesn't appear to be picking up certain metrics, like size_codebase, license, export_help, downloads_1yr, r_cmd_check, and covr_coverage (all have NAs).

@borgmaan suggested that this solution may help for covr_coverage because their only exists one s3 method, for "pkg_source". We should explore if it helps with any of the other missing metrics:

pkg_ref("/path/to/local/tidyCDISC", source = "pkg_source")