Add txnbuild/horizonclient CHANGELOG entries for release 7.0 (stellar…

…#3541)

Update changelog for 2.2.0 release (stellar#3539)

services/horizon/internal/ingest: Add retries in historyRangeState wh…

…en ledger is not available (stellar#3531)

Only consistency-check the Captive Core flags when captive-core inges…

…tion is enabled (stellar#3513)

services/horizon: Horizon 2.0.0 CHANGELOG (stellar#3429)

Update changelog for v6 txnbuild release (stellar#3420)

Fix PR link

Fix minor issues connected to reproducible builds (stellar#3408)

This commit fixes the following issues:
* Updates `check_release_hash` to use Golang version we use in Circle.
* Move `-ldflags` from command arguments to env variable. This has the same
effect but apparently the hash was different than the binary built by
`stellar/packages`.

services/horizon: Allow STELLAR_CORE_BINARY_PATH to be prefilled from…

… the PATH (stellar#3304)

all: use official docker images for publishing (stellar#3370)

### What

Use the official docker images for publishing Horizon to docker.

### Why

This is a follow up to stellar#3367 that changed us back to using the CircleCI convenience images after I made change stellar#3347. Instead of returning to use the buildpack-deps images I'm using the docker images because these tasks are building and pushing docker images, and so they should be perfect for this job.