Allow JavaTimeConversionPattern on fields

The registered converter already supported fields but the annotation did
 not.

junit-jupiter-params/src/main/java/org/junit/jupiter/params/converter/JavaTimeConversionPattern.java

@@ -34,7 +34,7 @@
  * @see org.junit.jupiter.params.ParameterizedTest
  * @see java.time.format.DateTimeFormatterBuilder#appendPattern(String)
  */
-@Target({ ElementType.ANNOTATION_TYPE, ElementType.PARAMETER })
+@Target({ ElementType.ANNOTATION_TYPE, ElementType.PARAMETER, ElementType.FIELD })
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 @API(status = STABLE, since = "5.7")