message: remove the last variable (sad) :(
diff: @@ -6,18 +6,13 @@ on:
  pull_request:
  branches: [ master, next ]
  -# here we group some parameters for later
  -env:
  - # see rust-version in Cargo.toml
  - MINIMUM_SUPPORTED_RUST_VERSION: "1.56.0"
  -
  jobs:
  build:
  name: Run tests and doctests on ubuntu
  runs-on: ubuntu-latest
  strategy:
  matrix:
  - rust: [${{ env.MINIMUM_SUPPORTED_RUST_VERSION }}, stable, beta, nightly]
  + rust: ["1.56.0", stable, beta, nightly]
  features: [gif, jpeg, png, tiff, ico, pnm, tga, webp, bmp, hdr, dxt, dds, farbfeld, openexr, jpeg_rayon, '']
  steps:
  - uses: actions/checkout@v2
  