Getting R versions to update automatically

.github/workflows/R-CMD-check.yaml

@@ -18,11 +18,11 @@ jobs:
       fail-fast: false
       matrix:
         config:
-          - {os: macOS-latest,   r: 'devel'}
-          - {os: macOS-latest,   r: '4.1'}
-          - {os: windows-latest, r: '4.1'}
-          - {os: ubuntu-18.04,   r: '4.1', rspm: "https://packagemanager.rstudio.com/cran/__linux__/bionic/latest"}
-          - {os: ubuntu-18.04,   r: '4.0', rspm: "https://packagemanager.rstudio.com/cran/__linux__/bionic/latest"}
+          - {os: macOS-latest,   r: 'release'}
+          - {os: windows-latest, r: 'release'}
+          - {os: ubuntu-16.04,   r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest", http-user-agent: "R/4.0.0 (ubuntu-16.04) R (4.0.0 x86_64-pc-linux-gnu x86_64 linux-gnu) on GitHub Actions" }
+          - {os: ubuntu-16.04,   r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
+          - {os: ubuntu-16.04,   r: 'oldrel',  rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
 
     env:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true

.github/workflows/test-coverage.yaml

@@ -28,8 +28,8 @@ jobs:
         uses: actions/cache@v1
         with:
           path: ${{ env.R_LIBS_USER }}
-          key: macOS-r-4.0-1-${{ hashFiles('.github/depends.Rds') }}
-          restore-keys: macOS-r-4.0-1-
+          key: macOS-r-4.0-2-${{ hashFiles('.github/depends.Rds') }}
+          restore-keys: macOS-r-4.0-2-
 
       - name: Install dependencies
         run: |