Removes code deprecated with v1.1.0

Signed-off-by: Meghana Jangi <[email protected]>

Author: meghanajangi

docs/book/src/developer/providers/v1.1-to-v1.2.md

@@ -21,7 +21,10 @@ in ClusterAPI are kept in sync with the versions used by `sigs.k8s.io/controller
 * `util.MachinesByCreationTimestamp` has been deprecated and will be removed in a future release.
 
 ### Removals
-
+* The `third_party/kubernetes-drain` package has been removed, as we're now using `k8s.io/kubectl/pkg/drain` instead ([PR](https://github.com/kubernetes-sigs/cluster-api/pull/5440)). 
+* `util/version.CompareWithBuildIdentifiers` has been removed, please use `util/version.Compare(a, b, WithBuildTags())` instead.
+* The functions `annotations.HasPausedAnnotation` and `annotations.HasSkipRemediationAnnotation` have been removed, please use
+  `annotations.HasPaused` and `annotations.HasSkipRemediation` respectively instead.
 -
 
 ### API Changes