lava: fix variables quoting for AUM tests

Without quoting they could be assumed as number which will lead to
incorrect usage. For instance build `20210119.0130` was cut to
`20210119.013` leading to incorrect path to delta URL construction.

Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>

lava/aum-tpl.yaml

@@ -22,14 +22,14 @@ job_name: Ostree updater test {{aum_test}} on {{release_version}} {{pretty}} {{i
           name: {{test_name}}-phase-{{phase}}
 {% endif %}
           params:
-            RELEASE: {{release_version}}
-            ARCH: {{arch}}
-            BASEURL: {{baseurl}}
-            IMGPATH: {{imgpath}}
-            IMGDATE: {{image_date}}
-            IMGTYPE: {{image_type}}
-            IMGNAME: {{image_name}}
-            BOARD: {{board}}
+            RELEASE: '{{release_version}}'
+            ARCH: '{{arch}}'
+            BASEURL: '{{baseurl}}'
+            IMGPATH: '{{imgpath}}'
+            IMGDATE: '{{image_date}}'
+            IMGTYPE: '{{image_type}}'
+            IMGNAME: '{{image_name}}'
+            BOARD: '{{board}}'
 {% endmacro %}
 {% for i in range(0,7) %}
 {{ run_test(aum_test, i, 6) }}