docs: vault integration docs should reference new token_explicit_max_ttl field

dev/vault/nomad-cluster-role.json

 {
   "disallowed_policies": "nomad-server",
-  "explicit_max_ttl": 0,
+  "token_explicit_max_ttl": 0,
   "name": "nomad-cluster",
   "orphan": false,
   "token_period": 259200,

e2e/vault/consts_test.go

@@ -35,10 +35,10 @@ var (
 	// role is the recommended nomad cluster role
 	role = map[string]interface{}{
 		"disallowed_policies": "nomad-server",
-		"explicit_max_ttl":    0,
+		"explicit_max_ttl":    0, // use old name for vault compatibility
 		"name":                "nomad-cluster",
 		"orphan":              false,
-		"period":              259200,
+		"period":              259200, // use old name for vault compatibility
 		"renewable":           true,
 	}
 

website/source/data/vault/nomad-cluster-role.json

 {
   "disallowed_policies": "nomad-server",
-  "explicit_max_ttl": 0,
+  "token_explicit_max_ttl": 0,
   "name": "nomad-cluster",
   "orphan": true,
   "token_period": 259200,

website/source/docs/vault-integration/index.html.md

@@ -138,7 +138,7 @@ An example token role definition is given below:
 ```json
 {
   "disallowed_policies": "nomad-server",
-  "explicit_max_ttl": 0,
+  "token_explicit_max_ttl": 0,
   "name": "nomad-cluster",
   "orphan": true,
   "token_period": 259200,
@@ -171,7 +171,7 @@ documentation for all possible fields and more complete documentation.
      Nomad. This was remedied in 0.6.5 and does not effect earlier versions
      of Vault.
 
-* `explicit_max_ttl` - Specifies the max TTL of a token. **Must be set to `0`** to
+* `token_explicit_max_ttl` - Specifies the max TTL of a token. **Must be set to `0`** to
   allow periodic tokens.
 
 * `name` - Specifies the name of the policy. We recommend using the name

website/source/guides/integrations/vault-integration/index.html.md

@@ -189,7 +189,7 @@ submitted to Nomad. We will use the following token role:
 ```json
 {
   "allowed_policies": "access-tables",
-  "explicit_max_ttl": 0,
+  "token_explicit_max_ttl": 0,
   "name": "nomad-cluster",
   "orphan": true,
   "token_period": 259200,
@@ -210,7 +210,7 @@ disallowed policies group. An example of this is shown below:
 ```json
 {
   "disallowed_policies": "nomad-server",
-  "explicit_max_ttl": 0,
+  "token_explicit_max_ttl": 0,
   "name": "nomad-cluster",
   "orphan": true,
   "token_period": 259200,