fix(ci,docker): update version string and optimize Dockerfile

.gitea/workflows/release-docker.yaml

@@ -7,7 +7,7 @@ on:
       - 'main'
 
 env:
-  VERSION: ${{ github.ref_name }}-${{ github.sha }}
+  VERSION: ${{ github.ref_name }}-${{ github.sha[0:7] }}
 
 jobs:
   docker:

Dockerfile

@@ -1,12 +1,11 @@
-FROM golang:latest
+FROM golang:latest as builder
-
+WORKDIR /app
-WORKDIR /usr/src/app
-
 COPY go.mod go.sum ./
 RUN go mod download
-
 COPY . .
-RUN go build -v -o /usr/local/bin/svg-templater ./...
+RUN go build -v -o svg-templater ./...
-RUN rm -rf ./*
 
-CMD ["svg-templater"]
+FROM alpine:latest
+WORKDIR /root/
+COPY --from=builder /app/svg-templater /usr/local/bin/svg-templater
+CMD ["./svg-templater"]