everest: fix version name

pkgs/by-name/ev/everest/package.nix

@@ -12,6 +12,7 @@
 let
   pname = "everest";
   version = "6170";
+  rev = "62ef4d0c36f433fa3a26502eabe6cda5ff205fbc";
   phome = "$out/lib/Celeste";
 in
 buildDotnetModule {
@@ -20,7 +21,7 @@ buildDotnetModule {
   src = fetchFromGitHub {
     owner = "EverestAPI";
     repo = "Everest";
-    rev = "62ef4d0c36f433fa3a26502eabe6cda5ff205fbc";
+    inherit rev;
     fetchSubmodules = true;
     # TODO: use leaveDotGit = true and modify external/MonoMod in postFetch to please SourceLink
     # Microsoft.SourceLink.Common.targets(53,5): warning : Source control information is not available - the generated source link is empty.
@@ -71,8 +72,7 @@ buildDotnetModule {
 
   preBuild = ''
     # See .azure-pipelines/prebuild.ps1
-    sed -i 's|0\.0\.0-dev|1.${version}.0-nixos-'$(git rev-parse --short=5 HEAD)'|' Celeste.Mod.mm/Mod/Everest/Everest.cs
-    cat Celeste.Mod.mm/Mod/Everest/Everest.cs
+    sed -i 's|0\.0\.0-dev|1.${version}.0-nixos-${lib.substring 0 5 rev}|' Celeste.Mod.mm/Mod/Everest/Everest.cs
     cat <<-EOF > Celeste.Mod.mm/Mod/Helpers/EverestVersion.cs
       namespace Celeste.Mod.Helpers {
         internal static class EverestBuild${version} {