ci: install missing package before script

Refs #61

.gitlab-ci.yml

@@ -9,6 +9,7 @@ default:
     - echo "setwd(\"$(pwd)\")" > .Rprofile
     - PATH=~/R/sources/R-${R_VERSION}/bin:$PATH
     - rename "s/${R_VERSION}.airGR/airGR/" *.tar.gz
+    - R -e 'chooseCRANmirror(graphics = FALSE, ind = 1); pkg <- "CaRamel"; pkgInst <- installed.packages()[, "Package"]; pkgMiss <- setdiff(pkg, pkgInst); if (length(pkgMiss) > 0) install.packages(pkgMiss)'
 
 .update_packages:
   stage: update_packages