Cirrus: Use human-readable CI VM Images

Image content hasn't changed much, the biggest thing here is the
`$IMAGE_SUFFIX` value.  This new schema is also fully manageable
by renovate.  Allowing a tag-push to c/automation_images to create image
update PRs in all repos automatically.

Signed-off-by: Chris Evich <cevich@redhat.com>

.cirrus.yml

@@ -32,10 +32,10 @@ env:
     ####
     #### Cache-image names to test with (double-quotes around names are critical)
     ####
-    FEDORA_NAME: "fedora-37"
+    FEDORA_NAME: "fedora-37" ### c20230120t152650z-f37f36u2204
 
     # Google-cloud VM Images
-    IMAGE_SUFFIX: "c6300530360713216"
+    IMAGE_SUFFIX: "c20230120t152650z-f37f36u2204"
     FEDORA_CACHE_IMAGE_NAME: "fedora-${IMAGE_SUFFIX}"
 
     # Container FQIN's (include bleeding-edge development-level container deps.)