Add a `riskmetrics` badge

```r
library(dplyr)
library(riskmetric)

x = pkg_ref(c("riskmetric", "crosstable", "dplyr", "EDCimport", "ggsurvfit", "utils", "tools")) %>%
  pkg_assess() %>%
  pkg_score()
x %>% 
  arrange(pkg_score) %>% 
  flextable()
```
https://github.com/pharmaR/riskmetric
Alternative : https://github.com/Sanofi-Public/risk.assessr
