Upgrade almalinux image to version 8.6

Change-Id: I7dcfde1d93e060774d0adc97f14ea757a404371d
diff --git a/almalinux/8/Dockerfile b/almalinux/8/Dockerfile
index 53bdb90..355b6f1 100644
--- a/almalinux/8/Dockerfile
+++ b/almalinux/8/Dockerfile
@@ -1,4 +1,4 @@
-FROM almalinux:8.5
+FROM almalinux:8.6
 MAINTAINER Gerrit Code Review Community
 
 # Add Gerrit packages repository