docs: Update future release dates

Signed-off-by: Anton Komlev <anton.komlev@arm.com>
Change-Id: I12d6335b884806e1357a53f0e081bf2df147222a
diff --git a/docs/releases/index.rst b/docs/releases/index.rst
index a794405..5bd493a 100644
--- a/docs/releases/index.rst
+++ b/docs/releases/index.rst
@@ -15,14 +15,6 @@
 +--------------------------------------+--------------+--------------------+----------------------------+
 | Version                              | Date         | Description        | PSA-arch tag/hash          |
 +======================================+==============+====================+============================+
-| v1.0-beta                            | 2019-02-15   | 1.0-beta release   |                            |
-+--------------------------------------+--------------+--------------------+----------------------------+
-| v1.0-RC1                             | 2019-05-31   | 1.0-RC1 release    | v19.06_API0.9              |
-+--------------------------------------+--------------+--------------------+----------------------------+
-| v1.0-RC2                             | 2019-10-09   | 1.0-RC2 release    | v19.06_API0.9              |
-+--------------------------------------+--------------+--------------------+----------------------------+
-| v1.0-RC3                             | 2019-11-29   | 1.0-RC3 release    | v19.06_API0.9              |
-+--------------------------------------+--------------+--------------------+----------------------------+
 | :doc:`v1.0 </docs/releases/1.0>`     | 2020-03-27   | 1.0 release        | v20.03_API1.0              |
 +--------------------------------------+--------------+--------------------+----------------------------+
 | :doc:`v1.1 </docs/releases/1.1>`     | 2020-07-15   | 1.1 release        | 1f960947                   |
@@ -44,10 +36,12 @@
 +--------------------------------------+-----------------+---------------+
 | Version                              | Feature Freeze  | Release       |
 +======================================+=================+===============+
-| v1.6.0                               | 2022-4-1        | 2022-4-15     |
+| v1.6.0                               | 2022-4-6        | 2022-4-28     |
 +--------------------------------------+-----------------+---------------+
 | v1.7.0                               | 2022-11-11      | 2022-11-30    |
 +--------------------------------------+-----------------+---------------+
+| v1.8.0                               | 2023-4-3        | 2023-4-28     |
++--------------------------------------+-----------------+---------------+
 
 Please refer to
 :ref:`docs/releases/release_process:Release Cadence and Process` for