ci.yml: fix push branch filter pattern (#502)

This fixes the branch regex to run Ubuntu workflows
on push to branches with a double digit major version
number.

Signed-off-by: Steve Peters <[email protected]>

Author: scpeters

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ on:
   push:
     branches:
       - 'ign-fuel-tools[0-9]'
-      - 'gz-fuel-tools[0-9]?'
+      - 'gz-fuel-tools[1-9]?[0-9]'
       - 'main'
 
 jobs: