update helm-doc binary version

[DaedalusG]

This needs updated in order for me to successfully run the sg release create temporal workflow for this repo. Working on that here: https://github.com/sourcegraph/sourcegraph/pull/7972

If I try to run the helm doc generation in the workflow I can't run a binary (this is a limitation or the temporal machine env which would need access the repo itself to run the binary.) To get around this issue I'm importing libraries that underly the helm-doc binary, but those libraries are built in a different version that helmdocs 1.7 and this is causing CI to fail https://buildkite.com/sourcegraph/deploy-sourcegraph-helm/builds/2379#019ade4b-d69f-42f0-850e-ed1ffdaaa0fd

The capital casing reflects a change in the publishers filename convention

Test plan

tested locally

[DaedalusG]

closing this PR since it would ultimately create an implicit versioning contract with the releaseworker service that the library code it uses is on the same version as the tool call here in the deploy repo 😢

Instead I'll investigate packaging the binary into the releaseworker msp service base image