Drop Node.js 18 support and add MySQL root password to fix CI

Co-authored-by: nomeguy <85475922+nomeguy@users.noreply.github.com>

Author: Copilot

.github/workflows/ci.yml

@@ -34,6 +34,7 @@ jobs:
         uses: mirromutth/mysql-action@v1.1
         with:
           mysql database: casbin
+          mysql root password: password
 
       - name: Set up Node.js
         uses: actions/setup-node@v2.1.5
@@ -57,21 +58,19 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       contents: read
-    strategy:
-      matrix:
-        node: ['18', '20']
     steps:
       - uses: actions/checkout@v2
 
       - name: Setup MySQL
         uses: mirromutth/mysql-action@v1.1
         with:
           mysql database: casbin
+          mysql root password: password
 
       - name: Set up Node.js
         uses: actions/setup-node@v3
         with:
-          node-version: ${{ matrix.node }}
+          node-version: 20
 
       - name: Install Dependency
         run: yarn install