Clarify MySQL setup action usage

.github/actions/setup-mysql-cluster/action.yml

@@ -3,7 +3,7 @@ description: Deploy MySQL on Docker
 inputs:
   provider:
     default: "docker"
-    description: "Deployment provider: docker"
+    description: "Deployment provider (currently only docker is supported)"
 
 runs:
   using: composite

.github/workflows/develop.yml

@@ -712,6 +712,8 @@ jobs:
       - if: matrix.mode.mysql
         name: Setup MySQL
         uses: ./.github/actions/setup-mysql-cluster
+        with:
+          provider: docker
 
       - name: Download pre-built binaries
         uses: actions/download-artifact@v4