feat: Add swift wasm CI targets to DataLoader

[scottmarchant]

Change summary

Added swift wasm as a CI target, to help prevent future breakages to swift wasm builds in DataLoader

Details

• Added ci stage that checks wasm compilation.
• Temporarily pointing to a branch of swift-nio to verify wasm compilation, as swift-nio/NIOCore is currently broken. The swift-nio version will be bumped before merging this.
• Bump swift version from 5.8 to 5.10.0, which is the new minimum for the latest swift-nio dependency.
• Add wasi 0.1 build status badge to README.md.

Notes

• Because the build status badge uses an unmerged workflow (.github/workflows/wasm.yaml), it can't be tested until this PR is merged. Some follow-on work may be needed after merging to ensure proper badge functionality.
• This PR is part of a larger effort by PassiveLogic to add wasm support to many popular repositories.

PR Dependencies

The following PR's must be merged before this PR can be merged:

• ci: Remove swift 5.8 and 5.9 builds from test matrix. Add Swift 6.1. ci#3
• fix: Fix compiler error found on latest main that breaks wasip1 (wasm) compilation apple/swift-nio#3271

Testing done

Verified new github workflow builds, once required upstream dependencies are patched in swift-nio

See https://github.com/PassiveLogic/DataLoader/actions/runs/15833601501/job/44631947127?pr=1

Remaining work

• Update this PR after swift-nio wasm build is merged and released
• After merging, verify badge works as expected. As noted, this can't be tested until after merging. Submit patch for new badge if needed.

[scottmarchant]

Note, this is likely a breaking change for users of this repository.

[scottmarchant]

The error for swift 5.8 should pass now that the ci change is merged.

error: 'dataloader': package 'dataloader' is using Swift tools version 5.10.0 but the installed version is 5.8.1