Temporarily run GitHub Actions on Windows, MacOS

.github/workflows/rust.yml

@@ -9,12 +9,13 @@ on:
 jobs:
   build:
     name: Run tests and doctests on ubuntu
-    runs-on: ubuntu-latest
     strategy:
       matrix:
+        os: [macos-latest, ubuntu-latest, windows-latest]
         rust: ["1.56.1", stable, beta, nightly]
         features: [webp-encoder]
 #        features: [gif, jpeg, png, tiff, ico, pnm, tga, webp, bmp, hdr, dxt, dds, farbfeld, openexr, jpeg_rayon, webp-encoder, '']
+    runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v2
     - uses: actions-rs/toolchain@v1
@@ -228,16 +229,16 @@ jobs:
       - uses: actions/checkout@v2
       - uses: EmbarkStudios/cargo-deny-action@v1
 
-  verify_msrv:
-    name: Verify Minimum Supported Rust Version in Cargo.toml
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-
-      - name: Install or use cached `cargo-msrv`
-        uses: baptiste0928/cargo-install@v1
-        with:
-          crate: cargo-msrv
-
-      - name: Verify Minimum Rust Version
-        run: cargo-msrv verify
+#  verify_msrv:
+#    name: Verify Minimum Supported Rust Version in Cargo.toml
+#    runs-on: ubuntu-latest
+#    steps:
+#      - uses: actions/checkout@v2
+#
+#      - name: Install or use cached `cargo-msrv`
+#        uses: baptiste0928/cargo-install@v1
+#        with:
+#          crate: cargo-msrv
+#
+#      - name: Verify Minimum Rust Version
+#        run: cargo-msrv verify