Temporary changes to trigger tests in k8s 1.21

- Adds an innocuous change to integration.yml so that all tests get
  triggered
- Hard-code k8s version in `k3d cluster create` invocation to v1.21

.github/workflows/integration.yml

@@ -1,5 +1,7 @@
 name: Integration tests
 
+# this comment changes this file, so all tests are triggered
+
 on:
   pull_request:
     paths:

bin/_test-helpers.sh

@@ -244,7 +244,7 @@ setup_cluster() {
 
   test_setup
   if [ -z "$skip_cluster_create" ]; then
-    "$bindir"/k3d cluster create "$@"
+    "$bindir"/k3d cluster create --image='+v1.21' "$@"
     image_load "$name"
   fi
   check_cluster