Add information about manifest specs in contribution guidelines

[#75039338]
Update pipeline image to include go in the path.
add doppler to loggregator deployments

[#75365570]

Signed-off-by: John Tuley <jtuley@pivotal.io>
bump loggregator

1a15d53 Improve test code formatting
e010144 Ensure doppler dump sinks only receive log messages
1693a55 expire varz metrics
f0391c7 Factor firehose websocket server away from app logs websocket server
27524a3 cleanup doppler websocket_server
3a4d9c9 metron message_aggregator: use stop event's app id
76862c6 connect traffic controller to doppler
d9aa1b6 Backporting syslog drain fix to Doppler
70e4ca3 implement firehose endpoint in doppler
fc31afc add firehose support to sink manager
cd64d1b add firehose support to grouped sinks
519ddbb shut down etcd heartbeat generator in between doppler tests
a30ac31 enable race condition check for all executables
a4f33f7 shut down etcd heartbeat generator in between tests
7e24287 bump dropsonde
5b63cde Extract ServerAddressProvider from OutputProxy
0a1b095 Use servicediscovery in trafficcontroller
0ee025d Go fmt
79b5266 Refactor trafficcontroller/dropsonde_proxy
049f41e Remove dropsonde listeners from loggregator
2eea038 Clean up doppler tests
6d04517 Remove WrappedEnvelope from doppler
7a19658 Add BOSH templates for doppler
9bc4b41 Add dropsondeOrigin flag; clean up tests
60e7dc7 add doppler process
79c18b6 bump loggregatorlib
2ca4f68 bump loggregatorlib
6592f69 bump loggregatorlib
1a21cb8 Merge branch 'develop'
52f9e73 add legacy message converter
996c9c3 improve test coverage
6597a0d Added unmarshalling for legacy Loggregator messages.
770a84d add legacy message converter
144bed0 improve test coverage
b02bb57 Added unmarshalling for legacy Loggregator messages.
9114d83 Remove unneeded Loggregators config var.