add cmp-fileName as example of using cmp

cmp-fileName/plugin-withFilename-config.yaml

@@ -0,0 +1,12 @@
+apiVersion: argoproj.io/v1alpha1
+kind: ConfigManagementPlugin
+metadata:
+  name: cmp-fileName
+spec:
+  version: v1.0
+  generate:
+    command: [sh, -c, 'echo "{\"kind\": \"ConfigMap\", \"apiVersion\": \"v1\", \"metadata\": { \"name\": \"$ARGOCD_APP_NAME\", \"namespace\": \"$ARGOCD_APP_NAMESPACE\", \"annotations\": {\"Foo\": \"$FOO\", \"KubeVersion\": \"$KUBE_VERSION\", \"KubeApiVersion\": \"$KUBE_API_VERSIONS\",\"Bar\": \"baz\"}}}"']
+  discover:
+    fileName: "./subdir/s*.yaml"
+  allowConcurrency: true
+  lockRepo: false