chore: remove Sourcehut CI manifest

Migrated to git.swaits.com; Sourcehut builds no longer run.

.build.yml

@@ -1,82 +0,0 @@
-image: archlinux
-packages:
-  - rustup
-  - cargo-audit
-  - cargo-deny
-  - cargo-msrv
-  - cargo-nextest
-  - cargo-outdated
-  - cargo-tarpaulin
-  - cargo-udeps
-secrets:
-  - 88cce185-d2ec-4573-9546-e33f36f79bbf
-sources:
-  - https://git.sr.ht/~swaits/vivaldi-nc
-artifacts:
-  - vivaldi-nc/tarpaulin-report.html
-tasks:
-  - setup: |
-      rustup toolchain install nightly stable
-      cd vivaldi-nc/
-      rustup run stable cargo fetch
-  - format: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo fmt --verbose --check --all
-  - lint: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo clippy --verbose --all-targets --all-features
-  - outdated: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo outdated
-  - deny: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo deny check
-  - udeps: |
-      rustup default nightly
-      cd vivaldi-nc/
-      cargo +nightly udeps --all-features
-  - audit: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo audit -d /tmp/advisory-db
-  - msrv: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo msrv verify
-  - coverage: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo tarpaulin --verbose --all-features --out html
-  - stable: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo build --verbose --all-targets --all-features
-      cargo nextest run --verbose --all-targets --all-features
-  - nightly: |
-      rustup default nightly
-      cd vivaldi-nc/
-      cargo clippy --verbose --all-targets --all-features  ||:
-      cargo build --verbose --all-targets --all-features   ||:
-      cargo nextest --verbose --all-targets --all-features ||:
-  - bench: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo bench --verbose --all-targets --all-features
-  - examples: |
-      rustup default stable
-      cd vivaldi-nc/
-      cargo run --verbose --all-features --example planetlab
-      cargo run --verbose --all-features --example planetlab --release
-  - docs: |
-      cd vivaldi-nc/
-      rustup run stable cargo doc --no-deps
-      rustup run nightly cargo doc --no-deps ||:
-  - mirror-to-github: |
-      cd ~/vivaldi-nc
-      ssh-keyscan -t rsa github.com >> ~/.ssh/known_hosts
-      git remote add github git@github.com:swaits/vivaldi-nc.git
-      git push --mirror github