Pin existing uses of `pathogen-repo-ci`

[joverlee521]

See #84 for context

Update the existing use of the pathogen-repo-ci across Nextstrain repos to pin them to ~https://github.com/nextstrain/.github/commit/ef5c51a9a3a22bde9243a090bbada0cd3a983f73 (since we have not tagged a specific version)~ v0 so that they continue to run as expected without having to conform the folder structure required by https://github.com/nextstrain/.github/pull/90.

Searched for pathogen-repo-ci with https://github.com/search?q=org%3Anextstrain+%2Fpathogen-repo-ci%5B.%5Dyaml%40%2F&type=code:

• [x] avian flu -> https://github.com/nextstrain/avian-flu/pull/59
• [x] conda-base -> updated as part of https://github.com/nextstrain/conda-base/pull/70
• [x] docker-base -> https://github.com/nextstrain/docker-base/pull/217
• [x] ebola -> https://github.com/nextstrain/ebola/pull/8
• [x] lassa -> https://github.com/nextstrain/lassa/pull/5
• [x] mumps -> https://github.com/nextstrain/mumps/pull/8
• [x] ncov -> https://github.com/nextstrain/ncov/pull/1115
• [x] rsv -> https://github.com/nextstrain/rsv/pull/64
• [x] rsv-old -> not updating since it's an archived repo
• [x] seasonal-flu -> https://github.com/nextstrain/seasonal-flu/pull/170
• [x] tb -> https://github.com/nextstrain/tb/pull/11

[genehack]

\ Maybe instead of pinning to https://github.com/nextstrain/.github/commit/ef5c51a9a3a22bde9243a090bbada0cd3a983f73, add a v0 tag to https://github.com/nextstrain/.github/commit/ef5c51a9a3a22bde9243a090bbada0cd3a983f73 and then pin to that? \

[joverlee521]

Maybe instead of pinning to [ef5c51a](https://github.com/nextstrain/.github/commit/ef5c51a9a3a22bde9243a090bbada0cd3a983f73), add a `v0` tag to [ef5c51a](https://github.com/nextstrain/.github/commit/ef5c51a9a3a22bde9243a090bbada0cd3a983f73) and then pin to that?

Didn't actually get to this today, since I got distracted by ncov-ingest, will do tomorrow.

Also noting that the commit hash ef5c51a9a3a22bde9243a090bbada0cd3a983f73 was copied over from the old issue. There's since been other updates in the repo before the pathogen-repo-ci update, so the v0 tag should be at baf4c033695f6d58dfa27a0febf750ce5fbb1817

[joverlee521]

Search query for pathogen-repo-ci@master only returns .github and seasonal-cov repos now 🎉