Simplify docs workflow dependencies

Author: gustavdelius

.github/workflows/docs.yml

@@ -30,16 +30,6 @@ jobs:
       - name: Set up R
         uses: r-lib/actions/setup-r@v2
 
-      - name: Install system libraries for R packages
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y libcurl4-openssl-dev libssl-dev libxml2-dev
-
-      - name: Install mizer in R
-        run: |
-          Rscript -e 'install.packages("remotes", repos = "https://cloud.r-project.org")'
-          Rscript -e 'remotes::install_github("sizespectrum/mizer")'
-
       - name: Install Python package with docs dependencies
         run: |
           python -m pip install --upgrade pip