fixup! Add helper script for creating GitHub releases using gh

overlay/github.nix

@@ -13,6 +13,12 @@
   # If 'release-tag' is 'autorelease' or 'PRERELEASE' env variable is set to 'true'
   # created release is marked as 'prerelease'.
   #
+  # 'OVERWRITE_RELEASE' env variable is set to 'true' an existing release with 'release-tag'
+  # will be deleted prior to recreation.
+  #
+  # This script expects 'GH_TOKEN' env variable to be set to a GitHub PAT that is capable of
+  # managing releases in the target repository.
+  #
   # Usage examples:
   # autorelease "$(nix build .#release)" "Automatic release on "$(date +\"%Y%m%d%H%M\")""
   #
@@ -25,9 +31,10 @@
       release_notes="$2";
       release_tag="''${3:-auto-release}"
 
-      # gh expects 'GH_TOKEN' env variable to be set
-      # Delete release if it exists
-      gh release delete "$release_tag" --yes || true
+      if [[ ''${OVERWRITE_RELEASE:-false} == true ]]; then
+        # Delete release if it exists
+        gh release delete "$release_tag" --yes || true
+      fi
 
       typeset -a release_args
       # Create release