Update automated build, remove Windows build

.github/workflows/gradle.yml

@@ -1,36 +1,24 @@
-# Automatically build the project and run any configured tests for every push
-# and submitted pull request. This can help catch issues that only occur on
-# certain platforms or Java versions, and provides a first line of defence
-# against bad commits.
-
 name: build
 on: [pull_request, push]
 
 jobs:
   build:
-    strategy:
-      matrix:
-        # Use these Java versions
-        java: [8]
-        # and run on both Linux and Windows
-        os: [ubuntu-20.04, windows-2022]
-    runs-on: ${{ matrix.os }}
+    if: "!contains(github.event.commits[0].message, '[ci-skip]')"
+    runs-on: ubuntu-latest
     steps:
       - name: checkout repository
         uses: actions/checkout@v2
       - name: validate gradle wrapper
         uses: gradle/wrapper-validation-action@v1
-      - name: setup jdk ${{ matrix.java }}
+      - name: setup jdk 8
         uses: actions/setup-java@v1
         with:
-          java-version: ${{ matrix.java }}
-      - name: make gradle wrapper executable
-        if: ${{ runner.os != 'Windows' }}
+          java-version: 8
+      - name: Make gradle wrapper executable
         run: chmod +x ./gradlew
-      - name: build
+      - name: Build
         run: ./gradlew build
-      - name: capture build artifacts
-        if: ${{ runner.os == 'Linux' && matrix.java == '8' }} # Only upload artifacts built from latest java on one OS
+      - name: Capture build artifacts
         uses: actions/upload-artifact@v2
         with:
           name: Artifacts