Describe the bug
When using a folded chomping block (>-) to specify the run command, it seems as though only the first line gets executed.

To Reproduce
Create a workflow like the following:

name: example
on: push
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - run: >-
          cargo test
            --verbose

Expected behavior
cargo test --verbose should be invoked.

Runner Version and Platform

Version of your runner? 2.168.0

OS of the machine running the runner? Ubuntu 18.04.4 LTS

What's not working?

It appears as though only cargo test is being invoked. The output of the step is not the verbose output of cargo.

Notes

The using an indent block works as expected, though I don't like needing to use shell escapes inside of YAML:

name: example
on: push
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - run: |
          cargo test \
            --verbose