Release 0.5.0

Bazel: Use --stamp command line flag (#3380)

This fixes the problem introduced by new version of go_rules,
the symptom being that StartupVersion was not set properly.

Fix deadlock in memrevcache (#1895)

The current memrevcache code will deadlock on Insert, every time: Insert
takes the write lock at the top, and later calls Get, which tries to get
the read lock. This is an automatic deadlock.

Also:
- Fix some log identifiers in go PS handlers.

PS: Add missing initialization of config (#1882)

Fix overlay port handling for BR in topology. (#1799)

It is (currently) illegal to specify `OverlayPort` in a BR entry, as the
BR doesn't run on top of the dispatcher. Additionally, calling
`OverlayAddr` on the internal address of a BR should set the overlay
port appropriately (assuming a UDP-based overlay).

Run CircleCI with machine executor and publish docker images (#1722)

Fix misleading docstring (#1697)