Ignore cache export error in conformance workflow

Author: Kate Osborn

.github/workflows/conformance.yml

@@ -127,7 +127,7 @@ jobs:
           context: "tests"
           load: true
           cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-to: type=gha,mode=max,ignore-error=true
           pull: true
 
       - name: Deploy Kubernetes