Documentation: Move 4.20 release notes to 4.20.1

This moves the release notes to 4.20.1, as was done with the 4.8 release
when it went to 4.8.1.  The index.md file is updated for both the 4.20.1
and 4.8.1 releases, and extra spacing was added. This doesn't get shown
in the output, but makes the text version look better.

Signed-off-by: Martin Roth <gaumless@gmail.com>
Change-Id: Ic2fb35f1bf9fa7dc16d324882cd6057a1a4b05ed
Reviewed-on: https://review.coreboot.org/c/coreboot/+/75637
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/Documentation/releases/coreboot-4.20-relnotes.md b/Documentation/releases/coreboot-4.20.1-relnotes.md
similarity index 100%
rename from Documentation/releases/coreboot-4.20-relnotes.md
rename to Documentation/releases/coreboot-4.20.1-relnotes.md
diff --git a/Documentation/releases/index.md b/Documentation/releases/index.md
index c6bec6e..bc57d3f 100644
--- a/Documentation/releases/index.md
+++ b/Documentation/releases/index.md
@@ -15,26 +15,26 @@
 
 ## Previous releases
 
-* [4.20 - May 2023](coreboot-4.20-relnotes.md)
-* [4.19 - January 2023](coreboot-4.19-relnotes.md)
-* [4.18 - October 2022](coreboot-4.18-relnotes.md)
-* [4.17 - May 2022](coreboot-4.17-relnotes.md)
-* [4.16 - February 2022](coreboot-4.16-relnotes.md)
-* [4.15 - November 2021](coreboot-4.15-relnotes.md)
-* [4.14 - May 2021](coreboot-4.14-relnotes.md)
-* [4.13 - November 2020](coreboot-4.13-relnotes.md)
-* [4.12 - May 2020](coreboot-4.12-relnotes.md)
-* [4.11 - November 2019](coreboot-4.11-relnotes.md)
-* [4.10 - July 2019](coreboot-4.10-relnotes.md)
-* [4.9 - December 2018](coreboot-4.9-relnotes.md)
-* [4.8 - May 2018](coreboot-4.8.1-relnotes.md)
-* [4.7 - January 2018](coreboot-4.7-relnotes.md)
-* [4.6 - April 2017](coreboot-4.6-relnotes.md)
-* [4.5 - October 2016](coreboot-4.5-relnotes.md)
-* [4.4 - May 2016](coreboot-4.4-relnotes.md)
-* [4.3 - January 2016](coreboot-4.3-relnotes.md)
-* [4.2 - October 2015](coreboot-4.2-relnotes.md)
-* [4.1 - July 2015](coreboot-4.1-relnotes.md)
+* [4.20.1 - May 2023](coreboot-4.20.1-relnotes.md)
+* [4.19   - January 2023](coreboot-4.19-relnotes.md)
+* [4.18   - October 2022](coreboot-4.18-relnotes.md)
+* [4.17   - May 2022](coreboot-4.17-relnotes.md)
+* [4.16   - February 2022](coreboot-4.16-relnotes.md)
+* [4.15   - November 2021](coreboot-4.15-relnotes.md)
+* [4.14   - May 2021](coreboot-4.14-relnotes.md)
+* [4.13   - November 2020](coreboot-4.13-relnotes.md)
+* [4.12   - May 2020](coreboot-4.12-relnotes.md)
+* [4.11   - November 2019](coreboot-4.11-relnotes.md)
+* [4.10   - July 2019](coreboot-4.10-relnotes.md)
+* [4.9    - December 2018](coreboot-4.9-relnotes.md)
+* [4.8.1  - May 2018](coreboot-4.8.1-relnotes.md)
+* [4.7    - January 2018](coreboot-4.7-relnotes.md)
+* [4.6    - April 2017](coreboot-4.6-relnotes.md)
+* [4.5    - October 2016](coreboot-4.5-relnotes.md)
+* [4.4    - May 2016](coreboot-4.4-relnotes.md)
+* [4.3    - January 2016](coreboot-4.3-relnotes.md)
+* [4.2    - October 2015](coreboot-4.2-relnotes.md)
+* [4.1    - July 2015](coreboot-4.1-relnotes.md)
 
 
 [checklist]: checklist.md