add build and publish workflow (#539)

- build and publish workflow
- publish on merge to main only
- ** do not merge until Package Settings have been changed to allow GHA
write to GHCR for this repo **

Author: thetoolsmith

.github/workflows/build.yml

@@ -0,0 +1,43 @@
+name: BuildImage
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Checkout GitHub Action'
+        id: checkout
+        uses: actions/checkout@v4
+
+      - name: Get Version
+        id: version
+        run: |
+          echo "TAG_VERSION=$(cat pyproject.toml | grep '^version.*$' | sed 's/version = //' | tr -d '\"' )" >> $GITHUB_ENV
+
+      - name: 'Build Image'
+        id: build
+        run: |
+          docker build -t ghcr.io/cfpb/regtech/sbl/sbl-filing-api-latest:latest -f Dockerfile .
+          docker tag ghcr.io/cfpb/regtech/sbl/sbl-filing-api-latest:latest ghcr.io/cfpb/regtech/sbl/sbl-filing-api:${{env.TAG_VERSION}}
+          docker tag ghcr.io/cfpb/regtech/sbl/sbl-filing-api-latest:latest ghcr.io/cfpb/regtech/sbl/sbl-filing-api:${{env.TAG_VERSION}}_${{github.run_number}}.${{github.run_attempt}}
+
+      - name: 'Login to GitHub Container Registry'
+        id: login
+        uses: docker/login-action@v3
+        if: github.ref == 'refs/heads/main' && steps.build.conclusion == 'success'
+        with:
+          registry: ghcr.io
+          username: ${{github.actor}}
+          password: ${{secrets.GITHUB_TOKEN}}
+
+      - name: 'Publish Image'
+        id: publish
+        if: github.ref == 'refs/heads/main' && steps.login.conclusion == 'success'
+        run: |
+          docker push ghcr.io/cfpb/regtech/sbl/sbl-filing-api-latest --all-tags
+