Export fusesoc-compatible release artifacts of iob_cache

[arturum1]

Update release-artifacts Makefile target to export pre-built iob_cache cores compatible with fusesoc.
Update README with info about these pre-built cores: https://github.com/arturum1/iob-cache?tab=readme-ov-file#pre-built-files

[Copilot]

Pull Request Overview

This PR updates the build process to generate FuseSoC-compatible release artifacts and updates the py2hwsw dependency to a newer commit.

• Updated py2hwsw dependency to commit 9ffb1d0fe9dc4585a747744d31924855ce9c9349 with corresponding SHA256 hash
• Introduced new fusesoc-export target and refactored the release-artifacts target to create FuseSoC-compatible pre-built cores
• Enhanced documentation to clarify that the pre-built versions are FuseSoC-compatible and provided instructions on how to use them

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
default.nix	Updates py2hwsw commit and SHA256 hash to a newer version
Makefile	Adds fusesoc-export target, updates release-artifacts to use FuseSoC export, and modifies clean target to remove fusesoc_exports directory
README.md	Clarifies that pre-built versions are FuseSoC-compatible, updates path to Verilog sources, and adds instructions for using cores in FuseSoC

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The tar command creates archives containing all files from the previous export. After line 85, the fusesoc_exports directory is not cleaned before the second export at line 86, which means the IOb archive will contain both AXI4 and IOb exports. Add a make clean or rm -rf fusesoc_exports between the two exports to ensure each archive contains only the correct interface files.

Suggested change

	tar -czf $(CORE)_axi_V$(VERSION).tar.gz ./fusesoc_exports/*
	tar -czf $(CORE)_axi_V$(VERSION).tar.gz ./fusesoc_exports/*
	@rm -rf fusesoc_exports

[arturum1]

The fusesoc-export target automatically calls clean: https://github.com/IObundle/iob-cache/pull/322/files/0a53fce0fb8bab5364d8ef42c420dfaedbbfed7b#diff-76ed074a9305c04054cdebb9e9aad2d818052b07091de1f20cad0bbac34ffb52R76

There is no need to manually remove the fusesoc_exports folder.