Merge pull request #54 from ChrisRackauckas-Claude/fix-ci-20251229

Fix CI: Update deprecated ubuntu-20.04 to ubuntu-latest

Author: ChrisRackauckas

.github/workflows/CI.yml

@@ -17,12 +17,11 @@ 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'}
+          - {os: ubuntu-latest, r: 'devel'}
 
     env:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
-      RSPM: ${{ matrix.config.rspm }}
 
     steps:
       - uses: actions/checkout@v4
@@ -54,7 +53,7 @@ jobs:
           while read -r cmd
           do
             eval sudo $cmd
-          done < <(Rscript -e 'writeLines(remotes::system_requirements("ubuntu", "20.04"))')
+          done < <(Rscript -e 'writeLines(remotes::system_requirements("ubuntu", "24.04"))')
       - name: Install dependencies
         run: |
           remotes::install_deps(dependencies = TRUE)