Drop yarn support and update pnpm

.github/workflows/package-manager-ci.yml

@@ -26,74 +26,8 @@ jobs:
       - name: Use pnpm
         uses: pnpm/action-setup@v2.4.0
         with:
-          version: ^6.0.0
+          version: ^9.0.0
       - name: Install dependancies
         run: pnpm install
       - name: Tests
         run: pnpm run test-ci-pnpm
-
-  yarn:
-    name: yarn package manager on ${{ matrix.node-version }} ${{ matrix.os }}
-    runs-on: ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [windows-latest, ubuntu-latest]
-        node-version: [20]
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
-      - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v4
-        with:
-          node-version: ${{ matrix.node-version }}
-      - name: Use yarn
-        run: |
-          yarn set version berry && yarn set version 2
-          echo "nodeLinker: node-modules" >> .yarnrc.yml
-          # see https://github.com/yarnpkg/berry/issues/2935#issuecomment-911299992
-          yarn add --dev typescript@~4.3.2
-          yarn install
-        env:
-          # needed due the yarn.lock file in pino's .gitignore
-          YARN_ENABLE_IMMUTABLE_INSTALLS: false
-      - name: Tests
-        run: yarn run test-ci
-
-  yarn-pnp:
-    name: yarn-pnp package manager on ${{ matrix.node-version }} ${{ matrix.os }}
-    runs-on: ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [windows-latest, ubuntu-latest]
-        node-version: [20]
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
-      - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v4
-        with:
-          node-version: ${{ matrix.node-version }}
-      - name: Use yarn
-        run: |
-          yarn set version berry
-          echo 'nodeLinker: pnp
-          packageExtensions:
-            debug@*:
-              dependencies:
-                supports-color: "*"
-            treport@*:
-              dependencies:
-                tap-yaml: "*"
-          ' >> .yarnrc.yml
-          yarn add --dev typescript@~4.3.2
-          yarn install
-          yarn add --dev transport@link:./test/fixtures/transport
-        env:
-          # needed due the yarn.lock file in pino's .gitignore
-          YARN_ENABLE_IMMUTABLE_INSTALLS: false
-      - name: Tests
-        run: yarn run test-ci-yarn-pnp