Fix "error: GitHub API: more that one release selected" in create-exe

[xdoardo]

Issue #5281 shows how, when running wasmer create-exe, an error occurs while downloading libwasmer from the latest release. It is due to the support of engines we recently introduced, which at the time did not allow their coexistence with "regular" engines (the sys ones), making separate releases (-wasmi, -wamr, -v8) necessary. We plan, in the short term, to have a release that allows the simultaneous existence of said engines, so the separate release won't be mandatory anymore - we will have to figure out which engines to ship by default and/or a mechanism to install the necessary libraries (e.g. libiwasm, libwee8..) when needed.

In the meantime, this patch fixes the current behaviour by filtering out the -wasmi, -wamr and -v8 releases upon download of libwasmer.