Fix branch name of camera-streamer

[Jyrka98]

Both the original and the forked fixed repo added in #280 use the "main" branch.

The "master" branch has not been updated in either of them since december 2023, and causes issues with newer rpi camera package updates

[mryel00]

Thanks for the PR, but there are two things bothering me:

1. The master branch is only used on Bullseye and will be changed to main on Bookworm. This didn't get any updates for libcamera for quite some time.
2. This PR would only change the branch in case of using a .config created with make config for multi instance setups. This gets also executed if KIAUH is detecting multiple instances. This set branch should get ignored on Bookworm (unintentionally) as you can see here

Therefore this PR should not be necessary, as it should always use main branch on Bookworm and master on Bullseye, as I intended it to be, that all Bullseye installations will be the same, old and new ones.

So before I can merge anything and before we discuss your problems here, please open a post in our discussions or on our discord that we can find out the real problem with your installation and then continue on this PR, if there is really a problem with the current code.

[Jyrka98]

Now that you mentioned that it sets it to main, I do see it in the log. I just did a third reinstall and the camera started working now without the change I made.

The reason I made the PR in the first place, was because it didn't work after the first reinstall, after which I started to look where the issue could be and noticed the different branch.

I guess whatever the issue was, it actually started working with the second reinstall done after this change, and it caused me to believe the "wrong" branch name was the reason.

I'll close this PR, sorry for the hasty submission.