docs: Updated kubectl apply command in manifests README (argoproj#4577)

Signed-off-by: Stefan Gloutnikov <stefan@gloutnikov.com>
Signed-off-by: Paul Brabban <paul.brabban@gmail.com>

manifests/README.md

@@ -4,13 +4,13 @@ Several sets of manifests are provided:
 
 | File | Description |
 |------|-------------|
-| [install.yaml](install.yaml) | Standard argo cluster-wide installation. Controller operates on all namespaces |
+| [install.yaml](install.yaml) | Standard argo cluster-wide installation. Controller operates on all namespaces. |
 | [namespace-install.yaml](namespace-install.yaml) | Installation of argo which operates on a single namespace. Controller does not require to be run with clusterrole. Installs to `argo` namespace as an example. |
 | [quick-start-minimal.yaml](quick-start-minimal.yaml) | Quick start including MinIO. Suitable for testing. |
 | [quick-start-mysql.yaml](quick-start-mysql.yaml) | Quick start including MinIO and MySQL. Suitable for testing. |
 | [quick-start-postgres.yaml](quick-start-postgres.yaml) | Quick start including MinIO and Postgres. Suitable for testing. |
 
-If installing with `kubectl install -f https://...`, remember to use the link to the file's raw version.
+If installing with `kubectl apply -f https://...`, remember to use the link to the file's raw version.
 Otherwise you will get `mapping values are not allowed in this context`.
 
 ## Kustomize