Update CI to current practices

Author: ctrueden

.github/workflows/build.yml

@@ -24,8 +24,10 @@ jobs:
           cache: 'maven'
       - name: Set up CI environment
         run: .github/setup.sh
+        shell: bash
       - name: Execute the build
         run: .github/build.sh
+        shell: bash
         env:
           GPG_KEY_NAME: ${{ secrets.GPG_KEY_NAME }}
           GPG_PASSPHRASE: ${{ secrets.GPG_PASSPHRASE }}