Add upgrade document about v0.9-v0.10.

Signed-off-by: RainbowMango <qdurenhongcai@gmail.com>

docs/upgrading/README.md

@@ -37,6 +37,7 @@ The `bases`,`patches`and `kustomization.yaml` now located at `charts/_crds` dire
 #### Manual Upgrade API
 
 **Step 1: Get the Webhook CA certificate**
+
 The CA certificate will be injected into `patches` before building the final CRD.
 We can retrieve it from the `MutatingWebhookConfiguration` or `ValidatingWebhookConfiguration` configurations, e.g:
 ```bash
@@ -50,6 +51,7 @@ sed -i'' -e "s/{{caBundle}}/${ca_string}/g" ./"charts/_crds/patches/webhook_in_c
 ```
 
 **Step2: Build final CRD**
+
 Generate the final CRD by `kubectl kustomize` command, e.g:
 ```bash
 kubectl kustomize ./charts/_crds 
@@ -66,3 +68,4 @@ Components upgrading is composed of image version update and possible command ar
 
 ## Details Upgrading Instruction
 ### [v0.8 to v0.9](./v0.8-v0.9.md)
+### [v0.9 to v0.10](./v0.9-v0.10.md)

docs/upgrading/v0.8-v0.9.md

@@ -3,4 +3,4 @@
 Nothing special other than the [Regular Upgrading Process](./README.md).
 
 ## Upgrading Notable Changes
-Please refer to [v0.9.0 Release Notes](https://github.com/karmada-io/karmada/releases/tag/v0.9.0).
+Please refer to [v0.9.0 Release Notes](https://github.com/karmada-io/karmada/releases/tag/v0.9.0) for more details.

docs/upgrading/v0.9-v0.10.md

@@ -0,0 +1,12 @@
+# v0.9 to v0.10
+
+Follow the [Regular Upgrading Process](./README.md).
+
+## Upgrading Notable Changes
+
+### karmada-scheduler
+
+The `--failover` flag has been removed and replaced by `--feature-gates`.
+If you enable fail over feature by `--failover`, now should be change to `--feature-gates=Failover=true`.
+
+Please refer to [v0.10.0 Release Notes](https://github.com/karmada-io/karmada/releases/tag/v0.10.0) for more details.