Add PMD suppressions with reason where appropriate.

Author: phipag

powertools-logging/src/main/java/software/amazon/lambda/powertools/logging/internal/LoggingManagerRegistry.java

@@ -28,7 +28,7 @@
 public final class LoggingManagerRegistry {
 
     // Used with double-checked locking within getLoggingManger()
-    @SuppressWarnings("java:S3077")
+    @SuppressWarnings({ "java:S3077", "PMD.AvoidUsingVolatile" })
     private static volatile LoggingManager instance;
 
     private LoggingManagerRegistry() {

powertools-logging/src/test/java/software/amazon/lambda/powertools/logging/internal/KeyBufferTest.java

@@ -333,6 +333,7 @@ void shouldUseCustomWarningLogger() {
     void shouldUseDefaultWarningLoggerWhenNotProvided() {
         // Capture System.err output
         ByteArrayOutputStream errCapture = new ByteArrayOutputStream();
+        @SuppressWarnings("PMD.CloseResource") // System.err is not ours to close
         PrintStream originalErr = System.err;
         try (PrintStream newErr = new PrintStream(errCapture)) {
             System.setErr(newErr);