ci: install lme4 via R, not via Python

.github/workflows/check.yml

@@ -45,16 +45,17 @@ jobs:
       uses: r-lib/actions/setup-r@v2
       with:
         r-version: '4.1.2'
-    - name: print R version
+    - name: Install R packages for lme4
       if: matrix.extras == 'all'
       shell: bash
-      run: R --version
+      run: |
+        R --version
+        R -e "install.packages(c('statmod','nloptr','lme4'),repos='http://cran.rstudio.org')"
     - name: Install dclab with all possible dependencies
       if: matrix.extras == 'all'
       run: |
         pip install -e .[all]
         pip install -r tests/requirements.txt
-        python -c "from dclab.lme4 import rsetup; rsetup.require_lme4()"
     - name: Install dclab with DCOR dependencies
       if: matrix.extras == 'dcor-s3'
       run: |