lambda-twiddle

Simple interface for modifying lambda environment variables.

``js
//Example usage
const AWS = require('aws-sdk');
const lambdaSdk = new AWS.Lambda({apiVersion: '2015-03-31'});
const lambdaArn = 'arn:aws:lambda:us-east-1:123456789012:function:ProcessRecords';
const variableChanges = {
environmentVariable1: 'string value 1',
environmentVariable1: 'string value 2'
};

const lambdaTwiddle = require('lambda-twiddle');
return lambdaTwiddle.environmentVariables({lambdaSdk, lambdaArn, variableChanges});
`

The environmentVariables function returns:
* A promise resolving to null if no call to AWS.Lambda.updateFunctionConfiguration(...) is required.
* The promise returned by AWS.Lambda.updateFunctionConfiguration(...).promise()`