Refactor the custom docker build/push GitHub workflow

Remove duplicate steps.
Reorganize the steps into discrete sections.

Both the checkout and docker buildx setup steps were present in the workflow file twice and while this didn't cause any problems running the workflow file it was confusing, unneeded (the buildx step is like installing a dependency and can happen anytime before the docker build/push step, as for the checkout step, everything was configured to use the code from the second checkout step thus making the first unnecessary), and probably slowed down its execution slightly.  Removing the duplicate steps and reorganizing the rest makes everything simpler and clearer.

.github/workflows/custom-docker-build-push.yml

@@ -46,6 +46,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      # Env variables
       - name: Assign username from secret
         if: ${{ inputs.Override_Registry_Username == ''}}
         run: |
@@ -74,23 +75,9 @@ jobs:
         run: |
           echo "repo_name=${GITHUB_REPOSITORY#*/}" >> "$GITHUB_ENV"
 
-      - name: Checkout code
-        uses: actions/checkout@v2
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
-        with:
-          install: true
-
-      - name: Login to container registry
-        uses: docker/login-action@v3
-        with:
-          registry: ${{ env.Registry_Base_URL }}
-          username: ${{ env.Registry_Username }}
-          password: ${{ env.Registry_Password }}
-
+      # Code
       - name: Checkout repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           path: "./repo"
 
@@ -103,11 +90,19 @@ jobs:
           mv ./_repo ./repo
           ls ./repo
 
-      - name: Docker Buildx setup
+      # Docker
+      - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
         with:
           install: true
 
+      - name: Login to container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.Registry_Base_URL }}
+          username: ${{ env.Registry_Username }}
+          password: ${{ env.Registry_Password }}
+
       - name: Docker Build and Push (with cache)
         if: ${{ fromJSON(env.Use_Build_Cache) == true }}
         uses: docker/build-push-action@v6