Update mco-update-boot-images-configuring.adoc to add correct label with "=" instead of ":"

Update mco-update-boot-images-configuring.adoc to add correct label with "=" instead of ":"

Author: aksjadha

modules/mco-update-boot-images-configuring.adoc

@@ -77,7 +77,7 @@ spec:
 If an appropriate label is not present on the machine set, add a key-value pair by running a command similar to following:
 
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-$ oc label machineset.machine ci-ln-hmy310k-72292-5f87z-worker-a region: "east" -n openshift-machine-api
+$ oc label machineset.machine ci-ln-hmy310k-72292-5f87z-worker-a region="east" -n openshift-machine-api
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