Update CI

Author: jeroen

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

@@ -16,10 +16,10 @@ jobs:
       fail-fast: false
       matrix:
         config:
-          - {os: macOS-latest,   r: 'release'}
-          - {os: windows-latest, r: '3.6'}
+          - {os: macos-latest,   r: 'release'}
           - {os: windows-latest, r: '4.1'}
           - {os: windows-latest, r: 'release'}
+          - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
           - {os: ubuntu-latest,   r: 'release'}
           - {os: ubuntu-latest,   r: 'oldrel-4'}
 
@@ -28,7 +28,7 @@ jobs:
       R_KEEP_PKG_SOURCE: yes
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - uses: r-lib/actions/setup-pandoc@v2