[build] Upgrade to spotbugs Gradle plugin 5.0.8 (#4310)

This fixes a SecurityManager deprecation warning generated by spotbugs.

wpilibjIntegrationTests/src/main/java/edu/wpi/first/wpilibj/AbstractInterruptTest.java

@@ -52,7 +52,7 @@ public abstract class AbstractInterruptTest extends AbstractComsSetup {
   abstract void setInterruptLow();
 
   @Test(timeout = 1000)
-  public void testSingleInterruptsTriggering() throws Exception {
+  public void testSingleInterruptsTriggering() {
     // Given
     // final InterruptCounter counter = new InterruptCounter();
     // TestInterruptHandlerFunction function = new