Retry R installations (#57)

Network failures were causing spurious CI failures; we now try to install ggplot2 (and its dependencies) up to three times.

.github/workflows/build.yml

@@ -45,7 +45,7 @@ jobs:
         
       - name: Benchmarks
         run: |
-          Rscript -e "install.packages('ggplot2', repos = 'https://cloud.r-project.org/')"
+          Rscript -e "tries <- 0; while (!require('ggplot2') && tries < 3) { cat(sprintf('TRY %d\n', tries)); install.packages('ggplot2', repos = 'https://cloud.r-project.org/'); tries <- tries + 1; }"
           PATH="$(pwd)/target/release:$PATH" ./run_bench.sh -n 3
           # grab latest directory (output of run_bench)
           DATADIR=bench/$(ls -ct bench/ | head -n 1)

.gitignore

@@ -3,3 +3,4 @@
 *.log
 *.png
 .Rhistory
+.DS_Store