Fix macOS GitHub Actions build failures

Two fixes to resolve macOS build failures in CI:

1. Upgrade setup-java from v1 to v4 with Temurin distribution
   - The old v1 action doesn't properly support ARM64 macOS runners
   - macos-latest now uses Apple Silicon (ARM64) machines
   - v4 automatically detects architecture and installs correct JDK

2. Add MAVEN_OPTS to fix JAXP XML entity size limit errors
   - Set maxGeneralEntitySizeLimit, totalEntitySizeLimit, and
     entityExpansionLimit to 0 to bypass XML parsing limits
   - Prevents "JAXP00010004: The accumulated size of entities
     exceeded the limit" errors during p2 repository parsing

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: robstryker

.github/workflows/actions.yml

@@ -22,17 +22,18 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Setup Java ${{ matrix.java }}
-      uses: actions/setup-java@v1
+      uses: actions/setup-java@v4
       with:
+        distribution: 'temurin'
         java-version: ${{ matrix.java }}
-        java-package: jdk # (jre, jdk, or jdk+fx) - defaults to jdk
-        architecture: x64
     - name: Setup node ${{ matrix.node }}
       uses: actions/setup-node@v4
       with:
         node-version: ${{ matrix.node }}
     - name: Build RSP part using Maven
       working-directory: rsp
+      env:
+        MAVEN_OPTS: -Djdk.xml.maxGeneralEntitySizeLimit=0 -Djdk.xml.totalEntitySizeLimit=0 -Djdk.xml.entityExpansionLimit=0
       run: mvn clean install -U -fae -e -B
     - name: Cache Version
       working-directory: vscode