emacsPackage.el-easydraw: fix passthru.updateScript

Use the same update script that is inlined in some other manual package derivations
as  has an incompatible version string format.

pkgs/applications/editors/emacs/elisp-packages/manual-packages/el-easydraw/default.nix

@@ -2,7 +2,7 @@
 , melpaBuild
 , fetchFromGitHub
 , writeText
-, unstableGitUpdater
+, writeScript
 , gzip
 }:
 
@@ -33,7 +33,19 @@ melpaBuild {
        "msg"))
   '';
 
-  passthru.updateScript = unstableGitUpdater { };
+  passthru.updateScript = writeScript "update.sh" ''
+    #!/usr/bin/env nix-shell
+    #!nix-shell -i bash -p common-updater-scripts coreutils git gnused
+    set -eu -o pipefail
+    tmpdir="$(mktemp -d)"
+    git clone --depth=1 https://github.com/misohena/el-easydraw.git "$tmpdir"
+    pushd "$tmpdir"
+    commit=$(git show -s --pretty='format:%H')
+    # Based on: https://github.com/melpa/melpa/blob/2d8716906a0c9e18d6c979d8450bf1d15dd785eb/package-build/package-build.el#L523-L533
+    version=$(TZ=UTC git show -s --pretty='format:%cd' --date='format-local:%Y%m%d.%H%M' | sed 's|\.0*|.|')
+    popd
+    update-source-version emacsPackages.el-easydraw $version --rev="$commit"
+  '';
 
   meta = {
     homepage = "https://github.com/misohena/el-easydraw";