Add Docker image build step to GitHub Actions workflow

- Introduced a new step to build the Docker image for the FastAPI application, enhancing the CI/CD process.
- The step includes output verification of the built image, ensuring successful creation.

Author: efraespada

.github/workflows/gbf_vector.yml

@@ -38,6 +38,14 @@ jobs:
         run: |
           echo "docker_host=unix://${HOME}/.colima/default/docker.sock" >> $GITHUB_OUTPUT
 
+      - name: Build Docker Image
+        env:
+          DOCKER_HOST: ${{ steps.docker-env.outputs.docker_host }}
+        run: |
+          cd docker
+          docker build -t fastapi-app .
+          docker images | grep fastapi-app
+
       - name: Run Vector Action
         uses: ./
         env: