Github Actions release to other repo

Currently I have the following code:

name: Build-All

    on: 
      push:
        branches: [ master ]
      pull_request:
        branches: [ master ]

    jobs:    
      build-linux-64:
        name: ${{ matrix.config.name }} Build
        runs-on: ${{ matrix.config.os }}
        strategy:
          fail-fast: true
          matrix:
            config:
              - os: ubuntu-latest
                name: Ubuntu 64
                other_linker_flags: '-m64'
                arch: x86_64
                output: myLib.so

        steps:
        - name: Make fake file
          run: |
            echo "hello" > ${{ github.workspace }}/test.txt

        - name: Uploading Release
          uses: ollydev/upload-release-action@master
          with:
            repo_token: XXXXXXXXX
            file: '${{ github.workspace }}/test.txt'
            asset_name: "test"
            tag: autobuild
            owner: '${{ github.repo.owner }}'
            repo: 'B'
            overwrite: true

and two repos: A and B.

Repo A has the above yml jobs and it is a private repo. It has all the code, compiles it, and wants to push the release to repo B which is public.

To do this, I created a new github account My-CI and I added it to both the private repo and the public repo. On that new account, I then created a Personal access token with scope: public_repo

and that's it. The code works.. but is there a way to NOT have to create a separate account just to give it access as a CI to both repos? IE: Is there a way that I can create a token on my real account that is read-only for one repo and read-write for another? OR maybe create a github app token or something that can only upload releases for the one repo (B)?

As you've implied, you can't limit the scope of a personal access token to different scopes for different repos. Theres a few ways of doing this.

Intermediate, public storage

The first is to upload the artifacts to an intermediate place, accessible from anywhere, e.g. Dropbox, Docker Hub, etc. Then you can manually trigger a github action in your public repo to pull this artifact back down and create a release from it. To manually trigger this action you could use the repository_dispatch event either using cURL / postman locally (with an access token auth bearer) or using something like https://www.actionspanel.app/ which is a github app which allows you to manually trigger github actions using repository_dispatch, with parameters so your download link would be a parameter.

Personal access token

The simplest option is still a personal access token though. Your workflow above has repo_token: XXXXXXXXX which makes me wonder if you know about github secrets? Ideally this token would be stored in a secret then accessed using ${{ secrets.BRANDONS_TOKEN }}. I would ask why you are worried about a personal access token. If you use github secrets and are careful about the 3rd party code you pass the token to (you may not want to simply pass your token to @master, for example), it should be fine.

GitHub Apps & Webhooks

GitHub apps or webhooks would be another way, you can authenticate those on a per-person basis and per-repo basis but you'd need an application running online to receive and parse the messages and its quite a big piece of work.

(Probably not) GitHub Deploy Keys

Another thing to be aware of is Github Deploy Keys, you can use these to obtain read/write access to a single repository without an account attached. You would then store this deploy key in a secret in the settings of the other repo. However, I'm not sure you can trigger releases with deploy keys - they are not bound to an account so I'm unsure who's username would be visible on the release history.