Update Docs for heroku_logs/logplex

[mms-gianni]

I am ingesting logs from Heroku and struggled configuring it.

The vector part is pretty good documented. But i missed the Heroku part. I took me a day to figure out how the drain should look like which i had to add with the Heroku-cli.

Here is what worked for me:

heroku drains:add "https://vector.mydomain.ch/events?application=myCustomAppTag" -a myApplication

But overall, still very happy with vector. Great work!

PS: Since the docs are generated, i was not able to open a PR.

[jszwedko]

Thanks @mms-gianni !

If you like, you could add it the docs by adding a section like:

vector/website/cue/reference/components/sources/aws_s3.cue

Lines 162 to 198 in 36b9243

	how_it_works: {
	events: {
	title: "Handling events from the `aws_s3` source"
	body: """
	This source behaves very similarly to the `file` source in that
	it will output one event per line (unless the `multiline`
	configuration option is used).
	You will commonly want to use [transforms](\(urls.vector_transforms)) to
	parse the data. For example, to parse VPC flow logs sent to S3 you can
	chain the `remap` transform:
	```toml
	[transforms.flow_logs]
	type = "remap" # required
	inputs = ["s3"]
	drop_on_error = false
	source = '''
	. = parse_aws_vpc_flow_log!(string!(.message))
	'''
	```
	To parse AWS load balancer logs, the `remap` transform can be used:
	```toml
	[transforms.elasticloadbalancing_fields_parsed]
	type = "remap" # required
	inputs = ["s3"]
	drop_on_error = false
	source = '''
	. = parse_aws_alb_log!(string!(.message))
	.request_url_parts = parse_url!(.request_url)
	'''
	```
	"""
	}
	}

to

https://github.com/vectordotdev/vector/blob/master/website/cue/reference/components/sources/heroku_logs.cue