automatically update readme hash

README.md

@@ -69,7 +69,7 @@ See the [mailing list archive](https://www.freelists.org/archive/snm/)
   imports = [
     (builtins.fetchTarball {
       url = "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/v2.3.0/nixos-mailserver-v2.3.0.tar.gz";
-      sha256 = "03d49v8qnid9g9rha0wg2z6vic06mhp0b049s3whccn1axvs2zzx";
+      sha256 = "0lpz08qviccvpfws2nm83n7m2r8add2wvfg9bljx9yxx8107r919";
     })
   ];
 

update.sh

@@ -1,3 +1,7 @@
 #!/usr/bin/env bash
 
 sed -i -e "s/v[0-9]\+\.[0-9]\+\.[0-9]\+/$1/g" README.md
+
+HASH=$(nix-prefetch-url "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/v2.3.0/nixos-mailserver-$1.tar.gz" --unpack)
+
+sed -i -e "s/sha256 = \"[0-9a-z]\{52\}\"/sha256 = \"$HASH\"/g" README.md