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#### Section/Content To Improve
https://github.com/axios/axios/blob/master/CHANGELOG.md

#### Suggested Improvement
Please add 0.21.1 to the Changelog.

#### Relevant File(s)
https://github.com/axios/axios/blob/master/CHANGELOG.md
dist/axios.js
if (!utils.isUndefined(config2[prop])) {
	      config[prop] = getMergedValue(config1[prop], config2[prop]);
	    } else if (!utils.isUndefined(config1[prop])) {
	      config[prop] = getMergedValue(undefined, config1[prop]);
	    }
	  }
	
	  utils.forEach(valueFromConfig2Keys, function valueFromConfig2(prop) {
	    if (!utils.isUndefined(config2[prop])) {
	      config[prop] = getMergedValue(undefined, config2[prop]);
	    }
	  });
	
	  utils.forEach(mergeDeepPropertiesKeys, mergeDeepProperties);
	
	  utils.forEach(defaultToConfig2Keys, function defaultToConfig2(prop) {
	    if (!utils.isUndefined(config2[prop])) {
	      config[prop] = getMergedValue(undefined, config2[prop]);
	    } else if (!utils.isUndefined(config1[prop])) {
	      config[prop] = getMergedValue(undefined, config1[prop]);
	    }
	  });
	
	  utils.forEach(directMergeKeys, function merge(prop) {
	    if (prop in config2) {
	      config[prop] = getMergedValue(config1[prop], config2[prop]);
	    } else if (prop in config1) {
	      config[prop] = getMergedValue(undefined, config1[prop]);