[DOCS] Adds placeholder for 6.4.1 release notes

Author: lcawl

docs/reference/release-notes.asciidoc

@@ -5,6 +5,7 @@
 --
 This section summarizes the changes in each release.
 
+* <<release-notes-6.4.1>>
 * <<release-notes-6.4.0>>
 * <<release-notes-6.3.2>>
 * <<release-notes-6.3.1>>

docs/reference/release-notes/6.4.asciidoc

@@ -6,7 +6,7 @@
 // TEMPLATE
 
 // [[release-notes-n.n.n]]
-// == {es} n.n.n
+// == {es} version n.n.n
 
 //[float]
 [[breaking-n.n.n]]
@@ -34,6 +34,36 @@
 //=== Known Issues
 ////
 
+[[release-notes-6.4.1]]
+== {es} version 6.4.1
+
+coming[6.4.1]
+
+//[float]
+//[[breaking-n.n.n]]
+//=== Breaking Changes
+
+//[float]
+//=== Breaking Java Changes
+
+//[float]
+//=== Deprecations
+
+//[float]
+//=== New Features
+
+//[float]
+//=== Enhancements
+
+//[float]
+//=== Bug Fixes
+
+//[float]
+//=== Regressions
+
+//[float]
+//=== Known Issues
+
 [[release-notes-6.4.0]]
 == {es} version 6.4.0