Merge branch '67-update-the-certified-distribution-matrix' into '1.3'

Resolve "update the certified distribution matrix"

Closes #67

See merge request fusiondirectory/dev-manual!113

source/fusiondirectory/distribution/certified-distribution.rst

@@ -4,22 +4,19 @@ Certified distributions
 
 We certify FusionDirectory with all the most common distributions, here is a table which summarizes the level of support by distribution and version.
 
-Fusiondirectory need at least PHP 5.6.
+ * FusionDirectory 1.3.1 need = PHP 7.3 
 
- * Fusiondirectory 1.3 need >= PHP 5.6 
- * Fusiondirectory 1.4 need >= PHP 7.0
+================= ========================
+DISTRIBUTION      FusionDirectory 1.3.1
+================= ========================
+Debian Buster     supported
+Debian Bullseye   not supported
+----------------- ------------------------
+Ubuntu 18.04 LTS  supported ²
+Ubuntu 20.04 LTS  not supported
+----------------- ------------------------
+Centos 7          supported
+Centos 8          not supported
+================= ========================
 
-================= ======================== =======================
-DISTRIBUTION      FusionDirectory 1.2      FusionDirectory 1.3
-================= ======================== =======================
-Debian Jessie     need a support contract  need a support contract
-Debian Stretch    not supported            supported
-Debian Buster     not supported            supported
------------------ ------------------------ -----------------------
-Ubuntu 16.04 LTS  need a support contract  supported
-Ubuntu 18.04 LTS  not supported            supported
-Ubuntu 20.04 LTS  not supported            work in progress
------------------ ------------------------ -----------------------
-Centos 7          need a support contract  supported
-Centos 8          not supported            not supported
-================= ======================== =======================
+² Need the ppa repository from the official maintainer of Debian/Ubuntu packages