ci: fix secret env name of docker-build (#731)

## Description

Closes: #XXXX
This PR fixes the env name of docker-build ci.
We don't have `DOCKERHUB_CALLISTO_REPO` in our github secret, so the
following CI is failing.
https://github.com/forbole/callisto/actions/runs/8610094925

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- [ ] included the correct [type
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in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
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- [ ] confirmed the correct [type
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in the PR title
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.github/workflows/docker-build.yml

@@ -24,7 +24,7 @@ jobs:
       - name: Prepare tags 🏷️
         id: prep
         run: |
-          DOCKER_IMAGE=${{ secrets.DOCKERHUB_CALLISTO_REPO }}
+          DOCKER_IMAGE=${{ secrets.DOCKERHUB_BDJUNO_REPO }}
           CHAIN_NAME="${{env.CHAIN_NAME}}"
           VERSION="${{env.GITHUB_VERSION}}"
           TAGS="${DOCKER_IMAGE}:${CHAIN_NAME}-${VERSION}"