Update Sourcegraph Docker insiders images

[sourcegraph-bot]

This PR contains the following updates:

Package	Update	Change
index.docker.io/sourcegraph/cadvisor	digest	8f44d97 -> c6f0693
index.docker.io/sourcegraph/frontend	digest	86ad76e -> 7cf91a6
index.docker.io/sourcegraph/github-proxy	digest	7758d4f -> 56122c6
index.docker.io/sourcegraph/gitserver	digest	36e5b53 -> fa5d4bc
index.docker.io/sourcegraph/grafana	digest	991eeaf -> 1f90567
index.docker.io/sourcegraph/jaeger-agent	digest	f4d39da -> 6a2439c
index.docker.io/sourcegraph/jaeger-all-in-one	digest	0a502e5 -> d5229df
index.docker.io/sourcegraph/precise-code-intel-worker	digest	f2b4afd -> 2790459
index.docker.io/sourcegraph/prometheus	digest	5d37e17 -> 30cd05b
index.docker.io/sourcegraph/query-runner	digest	f4e5e3b -> ee67e3a
index.docker.io/sourcegraph/repo-updater	digest	3fb8dfd -> 18450c5
index.docker.io/sourcegraph/searcher	digest	05ba70f -> c0efd5b
index.docker.io/sourcegraph/symbols	digest	e06f83a -> a484805

Source: https://github.com/sourcegraph/sourcegraph/pull/17228

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