ci: enable tumbleweed

This reverts commit 5c5c453219.

And removes the old python(2) pull in.

For some reason we get:
`Package python3-embed was not found in the pkg-config search path.`
with python38-devel but not with python310-devel. Let's bump it to that
version.

.github/workflows/main.yml

@@ -12,7 +12,7 @@ jobs:
 
     strategy:
       matrix:
-        flavor: [debian, fedora, ubuntu]
+        flavor: [debian, fedora, tumbleweed, ubuntu]
 
     name: Linux
     steps:

Dockerfile.tumbleweed

@@ -29,10 +29,8 @@ RUN zypper --non-interactive in --no-recommends \
   libuuid-devel \
   make \
   ncurses-devel \
-  python \
+  python310 \
-  python-devel \
+  python310-devel \
-  python38 \
-  python38-devel \
   readline-devel \
   sqlite3-devel \
   gdk-pixbuf-devel \