fix(dynamodb): the maximum number of nonKeyAttributes is 100, not 20 (a…

…ws#8186)

The validation for `nonKeyAttributes` count on the secondaryt indexes
was incorrectly checked at `20`, while the real limit is `100` (it has
been raised since the code was initially authored).

Fixes aws#8095

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-dynamodb/lib/table.ts

@@ -1114,9 +1114,9 @@ export class Table extends TableBase {
    * @param nonKeyAttributes a list of non-key attribute names
    */
   private validateNonKeyAttributes(nonKeyAttributes: string[]) {
-    if (this.nonKeyAttributes.size + nonKeyAttributes.length > 20) {
+    if (this.nonKeyAttributes.size + nonKeyAttributes.length > 100) {
       // https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html#limits-secondary-indexes
-      throw new RangeError('a maximum number of nonKeyAttributes across all of secondary indexes is 20');
+      throw new RangeError('a maximum number of nonKeyAttributes across all of secondary indexes is 100');
     }
 
     // store all non-key attributes

packages/@aws-cdk/aws-dynamodb/test/dynamodb.test.ts

@@ -1114,7 +1114,7 @@ test('error when adding a global secondary index with projection type INCLUDE, b
   const table = new Table(stack, CONSTRUCT_NAME, { partitionKey: TABLE_PARTITION_KEY, sortKey: TABLE_SORT_KEY });
   const gsiNonKeyAttributeGenerator = NON_KEY_ATTRIBUTE_GENERATOR(GSI_NON_KEY);
   const gsiNonKeyAttributes: string[] = [];
-  for (let i = 0; i < 21; i++) {
+  for (let i = 0; i < 101; i++) {
     gsiNonKeyAttributes.push(gsiNonKeyAttributeGenerator.next().value);
   }
 
@@ -1124,7 +1124,7 @@ test('error when adding a global secondary index with projection type INCLUDE, b
     sortKey: GSI_SORT_KEY,
     projectionType: ProjectionType.INCLUDE,
     nonKeyAttributes: gsiNonKeyAttributes,
-  })).toThrow(/a maximum number of nonKeyAttributes across all of secondary indexes is 20/);
+  })).toThrow(/a maximum number of nonKeyAttributes across all of secondary indexes is 100/);
 });
 
 test('error when adding a global secondary index with read or write capacity on a PAY_PER_REQUEST table', () => {