README: Switch to github actions badges
README: Switch to github actions badges

Fixes: #2195

Signed-off-by: Daniel Silverstone <3cc17a76d780e0cd3d87bad586a1c53967be5625@digital-scurf.org>

inejge/rustup.rs,inejge/rustup.rs,nodakai/rustup.rs,rust-lang/rustup,rust-lang/rustup,rust-lang/rustup,rust-lang/rustup,nodakai/rustup.rs,rust-lang/rustup,nodakai/rustup.rs,inejge/rustup.rs,nodakai/rustup.rs,inejge/rustup.rs,inejge/rustup.rs,nodakai/rustup.rs