Update R-CMD-check.yaml

v4 instead of v2, and use ubuntu-latest instead of hard-coding version

Author: vbaliga

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

@@ -24,8 +24,8 @@ jobs:
         config:
           - {os: windows-latest, r: 'release'}
           - {os: macOS-latest, r: 'release'}
-          - {os: ubuntu-20.04, r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
-          - {os: ubuntu-20.04, r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
+          - {os: ubuntu-latest, r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/jammy/latest"}
+          - {os: ubuntu-latest, r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/jammy/latest"}
 
     env:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
@@ -50,7 +50,7 @@ jobs:
 
       - name: Cache R packages
         if: runner.os != 'Windows'
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ${{ env.R_LIBS_USER }}
           key: ${{ runner.os }}-${{ hashFiles('.github/R-version') }}-1-${{ hashFiles('.github/depends.Rds') }}