drop macos test automation

.github/workflows/build.yml

@@ -5,33 +5,21 @@ on: [push, pull_request]
 jobs:
   build:
     name: Build
-    runs-on: ${{ matrix.os }}
-    env:
-      CGO_CFLAGS_ALLOW: -Xpreprocessor
-    strategy:
-      matrix:
-        os: [ubuntu-latest, macos-latest]
+    runs-on: ubuntu-latest
 
     steps:
       - name: Set up Go 1.x
         uses: actions/setup-go@v2
         with:
-          go-version: ^1.13
+          go-version: ^1.21
 
       - name: Check out code into the Go module directory
         uses: actions/checkout@v2
 
       - name: Install linux deps
-        if: matrix.os == 'ubuntu-latest'
         run: |
-          sudo apt-get -y install libopenjp2-7
           sudo apt-get -y install libvips-dev
 
-      - name: Install macos deps
-        if: matrix.os == 'macos-latest'
-        run: |
-          brew install vips
-
       - name: Get dependencies
         run: |
           go get -v -t -d ./...