GitHub service incorrectly fails to fetch access token

[lindhe]

I'm getting an error when trying to trigger a GitHub commit status notification. It says it "received non 2xx response status". That, per se, is true! But it should not fail, because the status code is in fact just "302 Found". 😄

$ argocd -n argocd admin notifications template notify github-commit-status-success argocd --recipient 'github:'
DEBU[0000] Sending request: POST /app/installations/1/access_tokens HTTP/1.1
Host: git.example.com
Accept: application/vnd.github.v3+json
Accept: application/vnd.github.v3+json
Authorization: Bearer <redacted>
Content-Type: application/json

null  service=github
DEBU[0000] Received response: HTTP/2.0 302 Found
Connection: close
Cache-Control: no-cache
Content-Security-Policy: default-src 'none'; base-uri 'self'; block-all-mixed-content; child-src git.example.com/assets-cdn/worker/; connect-src 'self' git.example.com www.githubstatus.com online.visualstudio.com/api/v1/locations github-production-repository-image-32fea6.s3.amazonaws.com github-production-release-asset-2e65be.s3.amazonaws.com insights.github.com wss://git.example.com; font-src 'self'; form-action 'self' git.example.com; frame-ancestors 'none'; frame-src 'self'; img-src * data:; manifest-src 'self'; media-src git.example.com; script-src 'self'; style-src 'unsafe-inline' 'self'; worker-src git.example.com/assets-cdn/worker/
Content-Type: text/html; charset=utf-8
Date: Wed, 26 Jul 2023 12:52:42 GMT
Location: https://git.example.com/login?return_to=https%3A%2F%2Fgit.example.com%2Fapp%2Finstallations%2F1%2Faccess_tokens
Permissions-Policy: interest-cohort=()
Referrer-Policy: origin-when-cross-origin, strict-origin-when-cross-origin
Server: GitHub.com
Set-Cookie: _fi_sess=<redacted>
Strict-Transport-Security: max-age=31536000; includeSubdomains
Vary: X-PJAX, X-PJAX-Container, Turbo-Visit, Turbo-Frame
X-Content-Type-Options: nosniff
X-Frame-Options: deny
X-Github-Request-Id: 38b6f266-036e-42aa-ac60-063e1d22536a
X-Runtime: 0.004097
X-Runtime-Rack: 0.008871
X-Xss-Protection: 0
  service=github
failed to notify 'github:': Post "https://git.example.com/api/v3/repos/foo/bar/statuses/99523bbf53929af04afd1295cbbebca81c18de09": could not refresh installation id 1's token: received non 2xx response status "302 Found" when fetching https://git.example.com/app/installations/1/access_tokens

Somewhat similar to #96.

[lindhe]

This is probably where it stems from:

https://github.com/bradleyfalzon/ghinstallation/blob/2c9ac4835be98b28099c542660c967871b0400fa/transport.go#L240-L243

[lindhe]

Related to bradleyfalzon/ghinstallation#98

[Cyanopus]

Together with @lindhe we tried to add /api/v3 to the enterpriseBaseUrl and it workarounds the missing redirect handling on the bradleyfalzon/ghinstallation#98
The following config(from chart values perspective) works:

notifiers:
  service.github: |
    enterpriseBaseURL: https://<enterprise_url>/api/v3
    appID: xxx
    installationID: xxx
    privateKey: $github-privateKey