node_pool disk_size_gb must be a number in docs

Author: avthart

autogen/main/README.md

@@ -167,7 +167,7 @@ The node_pools variable takes the following parameters:
 | auto_repair | Whether the nodes will be automatically repaired | true | Optional |
 | autoscaling | Configuration required by cluster autoscaler to adjust the size of the node pool to the current cluster usage | true | Optional |
 | auto_upgrade | Whether the nodes will be automatically upgraded | true (if cluster is regional) | Optional |
-| disk_size_gb | Size of the disk attached to each node, specified in GB. The smallest allowed disk size is 10GB | 100GB | Optional |
+| disk_size_gb | Size of the disk attached to each node, specified in GB. The smallest allowed disk size is 10GB | 100 | Optional |
 | disk_type | Type of the disk attached to each node (e.g. 'pd-standard' or 'pd-ssd') | pd-standard | Optional |
 {% if beta_cluster %}
 | effect | Effect for the taint | | Required |