Update Docker Hub credentials in workflow

Author: CoolyDucks

.github/workflows/docker-publish.yml

@@ -8,8 +8,6 @@ on:
     branches: [ "master", "main" ]
 
 env:
-  REGISTRY: ""
-  DOCKER_USER: "CoolyDucks" 
   IMAGE_NAME: "json"
 
 jobs:
@@ -29,14 +27,14 @@ jobs:
         if: github.event_name != 'pull_request'
         uses: docker/login-action@v3
         with:
-          username: ${{ env.DOCKER_USER }}
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Extract Docker metadata
         id: meta
         uses: docker/metadata-action@v5
         with:
-          images: ${{ env.DOCKER_USER }}/${{ env.IMAGE_NAME }}
+          images: ${{ secrets.DOCKERHUB_USERNAME }}/${{ env.IMAGE_NAME }}
           tags: |
             type=raw,value=latest
             type=semver,pattern={{version}}
@@ -51,4 +49,3 @@ jobs:
           labels: ${{ steps.meta.outputs.labels }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
-