[ISSUE #6] Fix DockerHub PASSWORD obtaining (#7)

* feat: add docker build manual and fix dockerhub push

* Use DOCKERHUB_TOKEN instead of DOCKERHUB_PASSWORD

Fixes #6 
diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 5e748a6..be2c833 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -32,7 +32,7 @@
         uses: docker/login-action@v2
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_PASSWORD }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
       - name: Build and push
         uses: docker/build-push-action@v4
         with: