GHA: Try actions/checkout@v3

Author: nicowilliams

.github/workflows/build-linux.yml

@@ -88,7 +88,7 @@ jobs:
           #sudo add-apt-repository ppa:ubuntu-toolchain-r/test
 
       - name: 'Checkout the JDK source'
-        uses: actions/checkout@v4
+        uses: actions/checkout@v3
 
       - name: 'Get the BootJDK'
         id: bootjdk