build_iwasm_release.yml: Add shared lib build

[midokura-xavi92]

So far, no workflows would attempt to build the shared version of the iwasm library (namely, vmlib).

Note that, as opposed to GC_EH_BUILD_OPTIONS and DEFAULT_BUILD_OPTIONS, the actual default options defined by the build system are assumed, for the sake of simplicity and avoiding repeated code.

[lum1n0us]

Are we planning to include a shared library in the final set of release binaries, or are we going to test the compilation of a shared library with each PR? If it's the former, then modifying build_iwasm_release.yml makes sense. However, if it's the latter, you might want to make changes to .github/workflows/compilation_on_* instead.

[midokura-xavi92]

Are we planning to include a shared library in the final set of release binaries, or are we going to test the compilation of a shared library with each PR? If it's the former, then modifying build_iwasm_release.yml makes sense. However, if it's the latter, you might want to make changes to .github/workflows/compilation_on_* instead.

I do not decide which artifacts should be built for release, so I assume the latter only for now. I will then update the PR to only modify _.github/workflows/compilation_on__*.