Update to fortran-support 2.2.2 and release 2.2.3

What is the new feature

Updates the bundled fortran-support from 2.2.1 to 2.2.2 and bumps iconmath to 2.2.3.

fortran-support 2.2.2 brings, among others:

• libfortran-support!144 (merged): provides OpenACC::OpenACC_Fortran to consumers when it is linked (the counterpart of !120 (merged))
• libfortran-support!141 (merged): missing mixed-precision variants of copy() for 1d arrays

How is it implemented

• get_library now fetches fortran-support by the tag 2.2.2 instead of the commit SHA of 2.2.1.
• Since libfortran-support!138 (merged), a fetched fortran-support only exports its target when it is the top-level project (FS_ENABLE_INSTALL defaults to PROJECT_IS_TOP_LEVEL). iconmath's own export then failed: install(EXPORT "iconmath-targets" ...) includes target "iconmath-support" which requires target "fortran-support" that is not in any export set. FS_ENABLE_INSTALL is now set to IM_ENABLE_INSTALL before fetching, so the fetched fortran-support exports its target whenever iconmath exports its own. An already installed or otherwise found fortran-support is used as before.
• Version bumped to 2.2.3. Together with !120 (merged), the release contains the fixes for consumers on systems where OpenACC is not set in the compiler flags (e.g. ragnarok on LUMI, icon/icon!921)

Mandatory steps before review

• Gitlab CI passes (Hint: use make format for linting)
• New feature is covered by additional unit tests
• Mark the merge request as ready by removing Draft:

Mandatory steps before merge

• Reviewed by a maintainer
• Incorporate review suggestions
• Remember to edit the commit message and select the proper changelog category (feature/bugfix/other)

You are not supposed to merge this request by yourself, the maintainers of libiconmath take care of this action!