fix: Documentation add ARGOCD_ENV_ prefix to AVP_SECRET variable

docs/config.md

@@ -125,7 +125,7 @@ data:
     - name: aws-avp
       generate:
         command: ["sh", "-c"]
-        args: ["argocd-vault-plugin generate -s ${AVP_SECRET} ./"]
+        args: ["argocd-vault-plugin generate -s ${ARGOCD_ENV_AVP_SECRET} ./"]
 ```
 
 Notice that the secret name is parametrized via an environment variable. This means each Argo app manifest can set `AVP_SECRET` to be the name of the Kubernetes secret that contains the configuration for the backend needed to generate its secrets.
@@ -238,4 +238,4 @@ spec:
           value: foo-team-namespace
 ```
 
-**Note**: Exposing tokens (like `AVP_ROLE_ID` or `AVP_SECRET_ID`) in plain-text in Argo CD app manifests should be avoided. Prefer to pass those tokens through one of the means mentioned above.
+**Note**: Exposing tokens (like `AVP_ROLE_ID` or `AVP_SECRET_ID`) in plain-text in Argo CD app manifests should be avoided. Prefer to pass those tokens through one of the means mentioned above.