Fix experimental k8s run (pulumi#1192)

Two small changes to the workflow definition.
Firstly 'concurrency' doesn't apply across a build matrix, so use
max-parallel instead.

Secondly, always run the infra cleanup even if the k8s job failed.

.github/workflows/cron.yml

@@ -71,7 +71,6 @@ jobs:
  - testing-unit-go
  kubernetes:
  name: kubernetes
- concurrency: kubernetes-${{ github.sha }}-${{ github.run_number }}
  needs: test-infra-setup
  env:
  PULUMI_EXPERIMENTAL: ${{ matrix.experimental }}
@@ -153,6 +152,7 @@ jobs:
  set -euo pipefail
  cd misc/test && go test . --timeout 4h -v -json -count=1 -short -parallel 40 --tags=all --run=TestAccKubernetes 2>&1 | tee /tmp/gotest.log | gotestfmt
  strategy:
+ max-parallel: 1
  fail-fast: false
  matrix:
  dotnet-version:
@@ -467,6 +467,8 @@ jobs:
  test-infra-destroy:
  name: test-infra-destroy
  needs: kubernetes
+ # Always clean up the test infrastructure even if the k8s jobs failed
+ if: ${{ always() }}
  runs-on: ${{ matrix.platform }}
  steps:
  - name: Install DotNet ${{ matrix.dotnet-version }}