fix format

Author: stanley-cheung

grpc-common-spring-boot/src/main/java/net/devh/boot/grpc/common/util/Constants.java.template

@@ -30,7 +30,7 @@ public final class Constants {
     /**
      * A constant that defines the instrumentation_source metric tag value
      */
-	public static final String INSTRUMENTATION_SOURCE_TAG_VALUE = "grpc-spring";
+    public static final String INSTRUMENTATION_SOURCE_TAG_VALUE = "grpc-spring";
 
 
     private Constants() {}