GHA test on oldrel-1 (R4.3) and oldre-2 (R4.2).

Think oldrel-1 should be OK, but oldrel-2 will fail to the change in how errors are reported in R/snapshot. Must check if they can be bypassed.

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

@@ -42,8 +42,8 @@ jobs:
           - {os: ubuntu-20.04,   r: 'release'}
 #          Temporary disable the below check plattforms as they fail due to a change in how R reports error from R<4.3 to R>=4.3,
 #          which gives a different output in the snapshots produced by testthat>=3.2.0
-#          - {os: ubuntu-20.04,   r: 'oldrel-1'}
-#          - {os: ubuntu-20.04,   r: 'oldrel-2'}
+          - {os: ubuntu-20.04,   r: 'oldrel-1'}
+          - {os: ubuntu-20.04,   r: 'oldrel-2'}
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}