ci(fix): missing dependency remotes

Refs #8

.gitlab-ci.yml

@@ -18,6 +18,7 @@ cache:
 before_script:
   - mkdir -p $R_LIBS_USER
   - echo "R_LIBS='$R_LIBS_USER'" > .Renviron
+  - R -q -e 'if (!require(remotes)) install.packages(c("remotes", "testthat"))'
   - R -q -e 'remotes::install_deps(dep = T)'
 
 test_all: