Revert to Alpine 3.11.2.

See also: gliderlabs/docker-alpine#539 and
grpc/grpc-go#3572.

Author: brocaar

Dockerfile

@@ -14,7 +14,7 @@ WORKDIR $PROJECT_PATH
 RUN make dev-requirements
 RUN make
 
-FROM alpine:latest AS production
+FROM alpine:3.11.2 AS production
 
 RUN apk --no-cache add ca-certificates
 COPY --from=development /chirpstack-gateway-bridge/build/chirpstack-gateway-bridge /usr/bin/chirpstack-gateway-bridge