20.0.0-rc1

What's Changed

• Generate for entry expired error by @sisuresh in #282
• Bump xdr by @dmkozh in #283
• Generate XDR DepthLimiter and depth-limited Read/WriteXdr by @jayz22 in #281
• Bump XDR by @dmkozh in #285
• Make SCError into a union to allow user errors to be u32 by @graydon in #286
• Update rust-version by @github-actions in #284
• Bump xdr by @dmkozh in #287
• Bump xdr by @dmkozh in #288
• Bump xdr by @dmkozh in #289
• Regen to pick up ContractCostType changes by @jayz22 in #290
• Bump xdr by @dmkozh in #292
• Update to reflect removal of SCSpecTypeSet by @graydon in #291
• Bump xdr by @dmkozh in #293
• Take change from txSOROBAN_RESOURCE_LIMIT_EXCEEDED to txSOROBAN_INVALID by @graydon in #295
• Run CI via in merge queue by @leighmcculloch in #297
• Update rust-version by @github-actions in #294
• Bump curr and next by @sisuresh in #298
• bump xdr by @sisuresh in #299
• Bump version to 20.0.0-rc1 by @github-actions in #302

Full Changelog: v0.0.17...v20.0.0-rc1