CI: Don't build on Windows

The GitHub builder has not enough RAM and it keeps failing and honestly I don't care. Contributions welcome

Author: piegamesde

.github/workflows/gradle.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, windows-latest]
+        os: [ubuntu-latest]
         jdk: [17]
     steps:
     - uses: actions/checkout@v2