Add Docker build for v0.3.x

Dockerfile

@@ -1,11 +1,15 @@
-FROM golang:1.16 as builder
+FROM golang:1.17 as builder
+
 WORKDIR /src/litestream
 COPY . .
+
 ARG LITESTREAM_VERSION=latest
+
 RUN --mount=type=cache,target=/root/.cache/go-build \
 	--mount=type=cache,target=/go/pkg \
 	go build -ldflags "-s -w -X 'main.Version=${LITESTREAM_VERSION}' -extldflags '-static'" -tags osusergo,netgo,sqlite_omit_load_extension -o /usr/local/bin/litestream ./cmd/litestream
 
+
 FROM alpine
 COPY --from=builder /usr/local/bin/litestream /usr/local/bin/litestream
 ENTRYPOINT ["/usr/local/bin/litestream"]