message: fix variable usage and try use array variables
diff: @@ -8,7 +8,9 @@ on:
  # here we group some parameters for later
  env:
  + # see rust-version in Cargo.toml
  MINIMUM_SUPPORTED_RUST_VERSION: 1.56.0
  + CRATE_FEATURES: (gif, jpeg, png, tiff, ico, pnm, tga, webp, bmp, hdr, dxt, dds, farbfeld, openexr, jpeg_rayon, '')
  jobs:
  build:
  @@ -16,8 +18,8 @@ jobs:
  runs-on: ubuntu-latest
  strategy:
  matrix:
  - rust: [$MINIMUM_SUPPORTED_RUST_VERSION, stable, beta, nightly]
  - features: [ gif, jpeg, png, tiff, ico, pnm, tga, webp, bmp, hdr, dxt, dds, farbfeld, openexr, jpeg_rayon, '' ]
  + rust: [${{ env.MINIMUM_SUPPORTED_RUST_VERSION }}, stable, beta, nightly]
  + features: ${{ env.CRATE_FEATURES }}
  steps:
  - uses: actions/checkout@v2
  - uses: actions-rs/toolchain@v1
  @@ -49,7 +51,7 @@ jobs:
  runs-on: ubuntu-20.04
  strategy:
  matrix:
  - features: [ gif, jpeg, png, tiff, ico, pnm, tga, webp, bmp, hdr, dxt, dds, farbfeld, openexr, jpeg_rayon, '' ]
  + features: ${{ env.CRATE_FEATURES }}
  # we need to limit the number of parallel jobs
  # so we artificially depend on another job
  