universal testing

Author: lorenzwalthert

.github/workflows/end-to-end.yml

@@ -7,7 +7,17 @@ name: end-2-end
 
 jobs:
   end-2-end:
-    runs-on: macOS-latest
+    runs-on: ${{ matrix.config.os }}
+
+    name: ${{ matrix.config.os }} (${{ matrix.config.r }})
+
+    strategy:
+      fail-fast: false
+      matrix:
+        config:
+          - {os: macOS-latest,   r: 'release'}
+          - {os: windows-latest, r: 'release'}
+          - {os: ubuntu-latest,   r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/bionic/latest", http-user-agent: "R/4.0.0 (ubuntu-18.04) R (4.0.0 x86_64-pc-linux-gnu x86_64 linux-gnu) on GitHub Actions" }
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
     steps: