Update env to 20.0.2

[jayz22]

Description

• Bump curr env version to 20.0.2
• Remove temporary cost type size fix introduced in 6c5d40f

Checklist

• Reviewed the contributing document
• Rebased on top of master (no merge commits)
• Ran clang-format v8.0.0 (via make format or the Visual Studio extension)
• Compiles
• Ran all tests
• If change impacts performance, include supporting evidence per the performance document

[sisuresh]

Should we wait until env is released? While core does use the git rev, the version endpoint reports the version number as well. Example -

src/stellar-core version
v21.0.0rc1-69-g07d3362eb
rust version: rustc 1.74.1 (a28077b28 2023-12-04)
soroban-env-host:
    curr:
        package version: 21.0.0
        git version: cd534ed18dc44368b26e0c5089756cd1bcde0bc1
        ledger protocol version: 21
        pre-release version: 0
        rs-stellar-xdr:
            package version: 21.0.0
            git version: 290d32a9a1b72a55406ecf1f67d8ec8839584659
            base XDR git version: 2ba4049554bb0564950e6d9213e01a60fc190f54
    prev:
        package version: 20.3.0
        git version: 93120b6b32cd910fcc224cbf6aec1333f771a8bc
        ledger protocol version: 20
        pre-release version: 0
        rs-stellar-xdr:
            package version: 20.1.0
            git version: 2e0f7f7d42fcd6c3c42eb0d65570fba9f5193d7e
            base XDR git version: cdc339f5e74a75e8e558fd1a853397da71f1659a

[jayz22]

Should we wait until env is released? While core does use the git rev, the version endpoint reports the version number as well. Example -

src/stellar-core version
v21.0.0rc1-69-g07d3362eb
rust version: rustc 1.74.1 (a28077b28 2023-12-04)
soroban-env-host:
    curr:
        package version: 21.0.0
        git version: cd534ed18dc44368b26e0c5089756cd1bcde0bc1
        ledger protocol version: 21
        pre-release version: 0
        rs-stellar-xdr:
            package version: 21.0.0
            git version: 290d32a9a1b72a55406ecf1f67d8ec8839584659
            base XDR git version: 2ba4049554bb0564950e6d9213e01a60fc190f54
    prev:
        package version: 20.3.0
        git version: 93120b6b32cd910fcc224cbf6aec1333f771a8bc
        ledger protocol version: 20
        pre-release version: 0
        rs-stellar-xdr:
            package version: 20.1.0
            git version: 2e0f7f7d42fcd6c3c42eb0d65570fba9f5193d7e
            base XDR git version: cdc339f5e74a75e8e558fd1a853397da71f1659a

yeah good point. Perhaps it's better to wait for the actual version then.

[dmkozh]

r+ 367d2c3