20.0.0-rc2.2

What's Changed

• Pin dependencies on soroban/stellar crates to fix that v20.0.0-rc2 was picking up new incompatible stable releases of dependencies that have been released with v20.0.0 by @leighmcculloch in #1182

Full Changelog: v20.0.0-rc2.1...v20.0.0-rc2.2