局部变量线程安全，优先使用StringBuilder替换StringBuffer (#4472)

Co-authored-by: 夏亮 <xialiang@newerabc.com>

filter/src/main/java/com/alibaba/otter/canal/filter/aviater/AviaterRegexFilter.java

@@ -109,11 +109,11 @@ public class AviaterRegexFilter implements CanalEventFilter<String> {
     private List<String> completionPattern(List<String> patterns) {
         List<String> result = new ArrayList<>();
         for (String pattern : patterns) {
-            StringBuffer stringBuffer = new StringBuffer();
-            stringBuffer.append("^");
-            stringBuffer.append(pattern);
-            stringBuffer.append("$");
-            result.add(stringBuffer.toString());
+            StringBuilder stringBuilder = new StringBuilder();
+            stringBuilder.append("^");
+            stringBuilder.append(pattern);
+            stringBuilder.append("$");
+            result.add(stringBuilder.toString());
         }
         return result;
     }