message: Updated readme to only run in nightly
  As per conversation in
diff: @@ -159,7 +159,7 @@ matrix:
  - rust: nightly
  before_cache: |
  - if [[ "$TRAVIS_RUST_VERSION" == stable ]]; then
  + if [[ "$TRAVIS_RUST_VERSION" == nightly ]]; then
  RUSTFLAGS="--cfg procmacro2_semver_exempt" cargo install cargo-tarpaulin
  fi
  @@ -169,7 +169,7 @@ script:
  - cargo test
  after_success: |
  - if [[ "$TRAVIS_RUST_VERSION" == stable ]]; then
  + if [[ "$TRAVIS_RUST_VERSION" == nightly ]]; then
  # Uncomment the following line for coveralls.io
  # cargo tarpaulin --ciserver travis-ci --coveralls $TRAVIS_JOB_ID
  