Improved assembly descriptor ID: `aws-lambda`.

[garretwilson]

I suggest changing the ID of this assembly descriptor from lambda-zip to aws-lambda.

If users configure the descriptor using <appendAssemblyId>false</appendAssemblyId>, then it won't make a difference to them.

But some of us may be producing several artifacts, using the Maven classifier facility. That is we may have:

• foo-1.2.3.jar
• foo-1.2.3-javadoc.jar
• foo-123-sources.jar
  etc.

In our case, we would want the assembly ID appended, to give us a classifier for our Zip file. Unfortunately Maven Assembly Plugin gives us no control over which classifier is used—we're forced to use the assembly ID. This would give us:

• foo-1.2.3.jar
• foo-1.2.3-javadoc.jar
• foo-123-sources.jar
• foo-123-lambda-zip.zip

This has two problems:

• "Lambda" means lots of things. We need to specify this has something to do with AWS. (Maybe my project puts out Azure artifacts, too.)
• The zip is redundant—this is a Zip file with a .zip extension. It's like saying foo-123-jar.jar.

Of course I can publish my own assembly descriptor, but it would be nice if there were one already everyone could use.

Do you accept pull requests?