chore(Cargo.toml): bump reqwest to 0.12.4

[vdice]

Bumps reqwest to 0.12.4 to resolve the dependency conflict seen when attempting to build:

$ cargo build --release
    Updating git repository `https://github.com/fermyon/spin`
    Updating crates.io index
    Updating git repository `https://github.com/bytecodealliance/wasm-pkg-tools/`
error: failed to select a version for `reqwest`.
    ... required by package `warg-client v0.7.0`
    ... which satisfies dependency `warg-client = "^0.7.0"` of package `wasm-pkg-loader v0.3.0 (https://github.com/bytecodealliance/wasm-pkg-tools/?rev=5384205af449179de07ad82ecf4bd42b171a2e40#5384205a)`
    ... which satisfies git dependency `wasm-pkg-loader` of package `spin-loader v2.6.0-pre0 (https://github.com/fermyon/spin?rev=bc86ff322cf3e1aee19e3001094a5231bcbcd9df#bc86ff32)`
    ... which satisfies git dependency `spin-loader` of package `cloud-plugin v0.9.0 (/Users/vdice/code/github.com/fermyon/cloud-plugin)`
versions that meet the requirements `^0.12.4` are: 0.12.5, 0.12.4

all possible versions conflict with previously selected packages.

  previously selected package `reqwest v0.12.2`
    ... which satisfies dependency `reqwest = "^0.12"` (locked to 0.12.2) of package `oci-distribution v0.11.0 (https://github.com/fermyon/oci-distribution?rev=7e4ce9be9bcd22e78a28f06204931f10c44402ba#7e4ce9be)`
    ... which satisfies git dependency `oci-distribution` (locked to 0.11.0) of package `cloud-plugin v0.9.0 (/Users/vdice/code/github.com/fermyon/cloud-plugin)`

failed to select a version for `reqwest` which could resolve this conflict

[vdice]

Sorry, @itowlson assisted me here. Turns out my cargo state was in a weird spot. I can now build on main. Closing.