feat(formulas): allow formula-level upstream branch via. pillar/config

Author: myii

pillar.example

@@ -43,6 +43,16 @@ ssf:
         ### and simply add your personal token at the top of the script
         source: salt://ssf/files/your_directory/git/git_30_create_PR.sh
 
+  ### Any customisations to the formulas can be made here, e.g. for testing purposes
+  ### Usually, this is unnecessary but a likely override could be an upstream tracking
+  ### branch that doesn't match the value set above, i.e. `ssf:git:branch:upstream`.
+  semrel_formulas:
+    ssf:
+      context:
+        git:
+          branch:
+            upstream: master
+
   ### No formulas or files are active by default
   ### State the formulas and files to work through when running the formula
   active:

ssf/config/formulas.sls

@@ -27,7 +27,7 @@ prepare-git-branch-for-{{ formula }}:
     - cwd: {{ ssf.formulas_path }}/{{ formula }}/
     - args: >-
         prepare-git-branch-for-{{ formula }}
-        {{ ssf.git.branch.upstream }}
+        {{ context.git.branch.upstream | d(ssf.git.branch.upstream) }}
         {{ context.git.branch.pr }}
         {{ context.git.commit.body | regex_escape }}
     - runas: {{ ssf.user }}