chore: update docker ci

Dockerfile

@@ -8,7 +8,7 @@ RUN go mod download
 RUN cd cmd/chainbridge && go build -o /bridge .
 
 # # final stage
-FROM debian:stretch-slim
+FROM debian:buster
 RUN apt-get -y update && apt-get -y upgrade && apt-get install ca-certificates wget -y
 RUN wget -P /usr/local/bin/ https://chainbridge.ams3.digitaloceanspaces.com/subkey-rc6 \
   && mv /usr/local/bin/subkey-rc6 /usr/local/bin/subkey \
@@ -18,4 +18,4 @@ RUN subkey --version
 COPY --from=builder /bridge ./
 RUN chmod +x ./bridge
 
-ENTRYPOINT ["./bridge"]
+ENTRYPOINT ["./bridge"]