Keep compiler explorer synced with the mainnet version of forc

[JoshuaBatty]

This PR adds a new GitHub Actions workflow that automatically updates Compiler Explorer and the Infra repos when a new forc version is released in the mainnet channel. As compiler explorer allows for multiple versions of a compiler, this ensures that new mainnet versions of the compiler are automatically added to godbolt.

The workflow:

• Triggers when channel-fuel-mainnet.toml is updated in the gh-pages branch
• Compares the old and new Forc versions
• When a version change is detected, runs the update-compiler-explorer tool

This automation eliminates manual steps and ensures Compiler Explorer stays up-to-date with the latest Sway compiler releases on mainnet.

[github-actions]

LCOV of commit 6140e94 during CI #2148

Summary coverage rate:
  lines......: 85.6% (2423 of 2832 lines)
  functions..: 54.0% (334 of 619 functions)
  branches...: 63.0% (290 of 460 branches)

Files changed coverage rate: n/a