OST_REPO_OWNER is not used for /api/image

[vildzi]

Provide environment information

ENV Flags Set:

• OST_GITHUB_ID
• OST_GITHUB_SECRET
• OST_TOKEN_SECRET
• OST_REPO_SLUG
• OST_REPO_BRANCH
• OST_REPO_OWNER

What browser are you using? (if relevant)

No response

How are you deploying your application? (if relevant)

No response

Describe the Bug

When a user who is not the owner of the repo (and OST_REPO_OWNER is set) is adding or viewing images in a post, a "Couldn't load image." error occurs.

Expected Behavior

OST_REPO_OWNER should be used when getting images from raw.githubusercontent.com if set rather than always using the current users username.

Link to reproduction - Issues with a link to complete (but minimal) reproduction code will be addressed faster

N/A - any deployment with OST_REPO_OWNER set will work to reproduce the issue

To Reproduce

• Log in to outstatic as a user who is not the owner of the repo
• Attach an image to a post

[avitorio]

@vildzi Thank you for this! I just merged your PR!