Update Sourcegraph Docker insiders images

[sourcegraph-bot]

This PR contains the following updates:

Package	Update	Change
index.docker.io/sourcegraph/cadvisor	digest	3cac885 -> 81ab4b5
index.docker.io/sourcegraph/frontend	digest	bf94ff0 -> d146a60
index.docker.io/sourcegraph/github-proxy	digest	83a33b0 -> c19d4f8
index.docker.io/sourcegraph/gitserver	digest	b0a06d0 -> a03f2ec
index.docker.io/sourcegraph/grafana	digest	b6d12df -> 41644f8
index.docker.io/sourcegraph/jaeger-agent	digest	2db03e2 -> bb3433e
index.docker.io/sourcegraph/jaeger-all-in-one	digest	206f855 -> bfc10d2
index.docker.io/sourcegraph/precise-code-intel-worker	digest	9ebc1c3 -> e6a18ce
index.docker.io/sourcegraph/prometheus	digest	6218834 -> 30bcacb
index.docker.io/sourcegraph/query-runner	digest	e1fd813 -> 1fe5f74
index.docker.io/sourcegraph/repo-updater	digest	bc9c4e6 -> 0c1762d
index.docker.io/sourcegraph/searcher	digest	6081a68 -> d8590a2
index.docker.io/sourcegraph/symbols	digest	7a5a2a2 -> 1a5e896

Source: https://github.com/sourcegraph/sourcegraph/pull/18295

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