message: disable experimental feature publish-lockfile for stable rust
diff: @@ -7,6 +7,7 @@ RUN apt-get update && \
  COPY . /opt/tarpaulin/
  RUN cd /opt/tarpaulin/ && \
  + sed -i -e 's/^\(^.*publish-lockfile.*$\)/#\1/' Cargo.toml && \
  RUSTFLAGS="--cfg procmacro2_semver_exempt" cargo install --path . && \
  rm -rf /opt/tarpaulin/ && \
  rm -rf /usr/local/cargo/registry/
  