Update maven.yml

Author: brendandburns

.github/workflows/maven.yml

@@ -32,7 +32,7 @@ jobs:
     name: GraalVM Maven Test
     steps:
       - uses: actions/checkout@v2
-      - uses: DeLaGuardo/setup-graalvm@3
+      - uses: DeLaGuardo/setup-graalvm@8bbfe44ef9c6f5c07e5af036a1bffd561c037d18
         with:
           graalvm-version: '19.3.0.java8'
       - name: Build with Maven