SBPF virtual machine v0.21.0

What's Changed

• elf: make text section consistent with rodata by @topointon-jump in #168
• elf: handle missing symbol tables in strict parser by @procdump in #176
• ci: move attestation to before publishing by @nbelenkov in #181
• Implement bucketed freelist for jit compilation memory by @cpubot in #180

New Contributors

• @topointon-jump made their first contribution in #168

Full Changelog: v0.20.0...v0.21.0