Add docs for Compose file v3.5 and v3.6 (#5912)

Signed-off-by: Joffrey F <joffrey@docker.com>

_includes/content/compose-matrix.md

@@ -2,6 +2,8 @@ This table shows which Compose file versions support specific Docker releases.
 
 | **Compose file format** | **Docker Engine release** |
 |  -------------------    |    ------------------     |
+|      3.6                |       18.02.0+            |
+|      3.5                |       17.12.0+            |
 |      3.4                |       17.09.0+            |
 |      3.3                |       17.06.0+            |
 |      3.2                |       17.04.0+            |

compose/compose-file/compose-versioning.md

@@ -281,12 +281,11 @@ Introduces the following additional parameters:
 ### Version 3.6
 
 An upgrade of [version 3](#version-3) that introduces new parameters. It is
-only available with Docker Engine version **17.12.0** and higher.
+only available with Docker Engine version **18.02.0** and higher.
 
 Introduces the following additional parameters:
 
-- [`tmpfs`](index.md#tmpfs) in volume definitions using the [Long Syntax](index.md#long-syntax-3)
-- `size` optional parameter for a tmpfs volume
+- [`tmpfs` size](index.md#long-syntax-3) for `tmpfs`-type mounts
 
 ## Upgrading
 

compose/compose-file/index.md

@@ -1676,7 +1676,8 @@ expressed in the short form.
 - `volume`: configure additional volume options
   - `nocopy`: flag to disable copying of data from a container when a volume is
     created
-
+- `tmpfs`: configure additional tmpfs options
+  - `size`: the size for the tmpfs mount in bytes
 
 ```none
 version: "3.2"