upgrade actions/setup-java to v4

Author: stephengold

.github/workflows/push.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-java@v3
+      - uses: actions/setup-java@v4
         with:
           distribution: 'zulu'
           java-version: 8
@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-java@v3
+      - uses: actions/setup-java@v4
         with:
           distribution: 'zulu'
           java-version: 11
@@ -33,7 +33,7 @@ jobs:
     runs-on: macOS-12
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-java@v3
+      - uses: actions/setup-java@v4
         with:
           distribution: 'zulu'
           java-version: 17
@@ -44,7 +44,7 @@ jobs:
     runs-on: windows-2022
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-java@v3
+      - uses: actions/setup-java@v4
         with:
           distribution: 'zulu'
           java-version: 21