Switch CI target to sha instead of ref

ansible/molecule/default/converge.yml

@@ -2,9 +2,9 @@
 - name: update previous release to newest release
   hosts: all
   tasks:
-    - name: set github ref as version when available
+    - name: set current github commit as version when available
       set_fact:
-        paperlessng_version: "{{ lookup('env', 'GITHUB_REF') | default('latest', True) }}"
+        paperlessng_version: "{{ lookup('env', 'GITHUB_SHA') | default('master', True) }}"
     - name: update to newest paperless-ng release
       include_role:
         name: ansible