Update ghcr.io image builds too

Missed this in my original username search. I made the same mistake in
hypcast, so I already know this solution works.

Author: featherbread

.github/workflows/mainline.yml

@@ -34,8 +34,8 @@ jobs:
       with:
         push: true
         tags: |
-          ghcr.io/ahamlinman/randomizer:latest
-          ghcr.io/ahamlinman/randomizer:${{ github.sha }}
+          ghcr.io/${{ github.repository }}:latest
+          ghcr.io/${{ github.repository }}:${{ github.sha }}
           ahamlinman/randomizer:latest
           ahamlinman/randomizer:${{ github.sha }}
         platforms: |