fix args and pass var

.github/workflows/image_creation.yaml

@@ -40,4 +40,4 @@ jobs:
           tags: git.maximotejeda.com/maximo/ddns:${{ github.ref_name }}
           build-args: |
                 version=${{ github.ref_name }}
-                SHORTSHA=${{ steps.vars.outputs.shortsha }}
+                SHORTSHA=${{ steps.calculate-short-sha.outputs.shortsha }}

Dockerfile

@@ -9,7 +9,7 @@ COPY . .
 RUN go build -o bin/ddns \
     -ldflags "-X main.Shortsha=${SHORTSHA} \
     -X main.Version=${version} \
-    -X main.Aarch=${TARGETPLATFORM}" ./cmd
+    -X main.Aarch=${BUILDPLATFORM}" ./cmd
 
 FROM alpine AS runner
 COPY --from=builder /app/bin/ddns /usr/bin/