increase version to 20.0.0 (see note below)

With start of Kodi 20 Nexus, takes addon as major the same version number as Kodi.
This done to know easier to which Kodi the addon works.

For here now used by Kodi 20 Nexus.

visualization.matrix/addon.xml.in

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <addon
   id="visualization.matrix"
-  version="1.0.1"
+  version="20.0.0"
   name="Matrix"
   provider-name="Sarbes">
   <requires>@ADDON_DEPENDS@</requires>

visualization.matrix/changelog.txt

@@ -1,3 +1,11 @@
+20.0.0
+- Update dependency kissfft to version 131.1.0 (16. Feb. 2021)
+- Update dependency stb_image.h to version 2.27 (11. Jul. 2021)
+- Language translation updates by Weblate
+- Change test builds to 'Kodi 20 Nexus'
+- Increase version to 20.0.0
+  - With start of Kodi 20 Nexus, takes addon as major the same version number as Kodi.
+    This done to know easier to which Kodi the addon works.
 1.0.1
 - Fixed German translation (did not work at all before)
 1.0.0
@@ -12,7 +20,7 @@
 - Fix Debian build code
 - Add license file, add license and source URL to addon.xml
 0.4.2
-- Pre-Relese version for Kodi Matrix
+- Pre-Release version for Kodi Matrix
 0.2.0
 - Major features done
 0.0.1