gh actions: switch to actions/setup-java@v4

.github/workflows/main.yml

@@ -56,7 +56,7 @@ jobs:
         steps:
         - uses: actions/checkout@main
         - uses: seanmiddleditch/gha-setup-ninja@master
-        - uses: actions/setup-java@v2
+        - uses: actions/setup-java@v4
           with:
             distribution: 'zulu'
             java-version: '8'