Use `perl-utils` instead of custom written shasum (#67)

.ci/shasum

@@ -1,16 +0,0 @@
-#!/bin/bash
-shift
-ALGO=$1
-shift
-case $ALGO in
-  1)
-    sha1sum $@
-    ;;
-  256)
-    sha256sum $@
-    ;;
-  *)
-    >&2 echo "Algorithm $ALGO not found"
-    exit 1
-    ;;
-esac

Dockerfile

@@ -1,7 +1,6 @@
 FROM frolvlad/alpine-glibc
 
-RUN apk add --no-cache nodejs bash npm curl g++ make m4 patch gmp-dev perl git jq
-ADD .ci/shasum /usr/bin/shasum
+RUN apk add --no-cache nodejs bash npm curl g++ make m4 patch gmp-dev perl git jq perl-utils
 
 USER root