Update the ruleConfigs.json

[mchoi8739]

I am working on adding code snippets of rule configuration to the Debugger dev guide.
I am referring to the following source codes in order to see what default collections are taken by each rule.

• https://github.com/awslabs/sagemaker-debugger-rulesconfig/blob/master/smdebug_rulesconfig/rule_config_jsons/ruleConfigs.json
• https://github.com/awslabs/sagemaker-debugger-rules/tree/master/smdebug_rules

In the ruleConfigs.json, some rules have default collections, but some are missing them.
I suggest to add a default tensor collection to those rules that currently don't have it.

For example, in order for the XGBoost TreeDepth rule to work, we need to add the tree collection by default as following:

  "TreeDepth": {
    "DebugRuleConfiguration": {
      "RuleConfigurationName": "TreeDepth",
      "RuleParameters": {
        "rule_to_invoke": "TreeDepth"
      }
    },
    "CollectionConfigurations": [
      {
        "CollectionName": "tree",
        "CollectionParameters": {
          "save_interval": "500"
        }
      }
    ]
  },