Raise visibility of method DefaultColumnDefinitions.valueOf()

Author: Alexandre Dutra

core/src/main/java/com/datastax/oss/driver/internal/core/cql/DefaultColumnDefinitions.java

@@ -31,7 +31,7 @@
 @Immutable
 public class DefaultColumnDefinitions implements ColumnDefinitions {
 
-  static ColumnDefinitions valueOf(List<ColumnDefinition> definitions) {
+  public static ColumnDefinitions valueOf(List<ColumnDefinition> definitions) {
     return definitions.isEmpty()
         ? EmptyColumnDefinitions.INSTANCE
         : new DefaultColumnDefinitions(definitions);