Revert "build: temporarily disable illumos for release"

This reverts commit c0c401efeb.

.github/workflows/build-syncthing.yaml

@@ -164,7 +164,7 @@ jobs:
     needs:
       - build-test
       - package-linux
-      # - package-illumos
+      - package-illumos
       - package-cross
       - package-source
       - package-debian
@@ -646,7 +646,7 @@ jobs:
     needs:
       - codesign-windows
       - package-linux
-      # - package-illumos
+      - package-illumos
       - package-macos
       - package-cross
       - package-source