ci: ensure ESLint works with at least 9.15.0 and pre-releases (#365)

Author: lumirlumir

.github/workflows/ci.yml

@@ -28,11 +28,14 @@ jobs:
             fail-fast: false
             matrix:
                 os: [ubuntu-latest]
+                eslint: [9.15.0, 9.x, ^10.0.0-rc.0]
                 node: [25.x, 24.x, 22.x, 20.x, "20.19.0"]
                 include:
                     - os: windows-latest
+                      eslint: "latest"
                       node: "lts/*"
                     - os: macOS-latest
+                      eslint: "latest"
                       node: "lts/*"
         runs-on: ${{ matrix.os }}
         steps:
@@ -42,6 +45,8 @@ jobs:
                   node-version: ${{ matrix.node }}
             - name: Install dependencies
               run: npm install
+            - name: Install ESLint@${{ matrix.eslint }}
+              run: npm install -D eslint@${{ matrix.eslint }}
             - name: Run tests
               run: npm run test
     test_types: