message: don't rebuild `build.rs` if it hasn't been modified
  Copy and `touch` `build.rs` before copying source
diff: @@ -39,10 +39,14 @@ RUN cargo build --release
  # build. The touch on all the .rs files is needed, otherwise cargo assumes the
  # source code didn't change thanks to mtime weirdness.
  RUN rm -rf src build.rs
  -COPY --chown=cratesfyi src src/
  +
  COPY --chown=cratesfyi build.rs build.rs
  +RUN touch build.rs
  +COPY --chown=cratesfyi src src/
  +RUN find src -name "*.rs" -exec touch {} \;
  COPY --chown=cratesfyi templates/style.scss templates/
  -RUN touch build.rs && find src -name "*.rs" -exec touch {} \; && cargo build --release
  +
  +RUN cargo build --release
  ADD templates templates/
  ADD css $CRATESFYI_PREFIX/public_html
  