Clear github runner linux space

Signed-off-by: Andrew Leonard <anleonar@redhat.com>

.github/workflows/build.yml

@@ -64,6 +64,11 @@ jobs:
             variant: bisheng
             image: adoptopenjdk/centos7_build_image
     steps:
+    - name: Delete github runner stuff not needed to make space
+      run: |
+        sudo rm -rf /usr/share/dotnet
+        sudo docker image prune --all --force
+
     - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
 
     - name: Build Linux