CI: Do not use R for triggered CI runs

Since in any case asv_runner changes do not have anything to do with the
statistical checks run in ASV and validated against R

.github/workflows/triggered.yml

@@ -20,7 +20,6 @@ jobs:
       matrix:
         os: ["ubuntu-latest"]
         python-version: ["3.8", "3.12", "pypy-3.10"]
-        r-version: ['release']
     timeout-minutes: 30
     steps:
       - uses: actions/checkout@v4
@@ -44,11 +43,6 @@ jobs:
       - name: Setup a browser for more tests
         uses: browser-actions/setup-chrome@latest
 
-      - name: Set up R version ${{ matrix.r-version }}
-        uses: r-lib/actions/[email protected]
-        with:
-          r-version: ${{ matrix.r-version }}
-
       - name: Install dependencies
         run: python -m pip install ".[test,hg]"