Missing source tarball with submodules

**Is your feature request related to a problem? Please describe.** The latest release is missing the `nyxt-<version>-source-with-submodules.tar.xz` tarball that has been included in previous releases. This makes it harder to package Nyxt for distributions that require all sources (including submodules) to be available offline at build time. **Describe the solution you'd like** Please attach the `nyxt-<version>-source-with-submodules.tar.xz` tarball to the latest release assets, as has been done for previous releases. **Describe alternatives you've considered** Manually cloning the repository and fetching submodules, but this is not suitable for sandboxed/offline build environments. **Additional context** N/A