add a cli flag

contentctl/actions/release_notes.py

@@ -114,7 +114,10 @@ def release_notes(self, config:release_notes) -> None:
             #If a branch name is supplied, compare against develop
             if config.latest_branch not in repo.branches:
                 raise ValueError(f"latest branch {config.latest_branch} does not exist in the repository. Make sure your branch name is correct")
-            compare_against = "develop"
+            if config.compare_against not in repo.branches:
+                compare_against = config.compare_against
+            else:
+                compare_against = "develop"
             commit1 = repo.commit(config.latest_branch)
             commit2 = repo.commit(compare_against)    
             diff_index = commit2.diff(commit1)

contentctl/objects/config.py

@@ -966,6 +966,7 @@ class release_notes(Config_Base):
     new_tag:Optional[str] = Field(None, description="Name of the tag containing new content. If it is not supplied,"
                                           " then it will be inferred as the newest tag at runtime.")
     latest_branch:Optional[str] = Field(None, description="Branch for which we are generating release notes")
+    compare_against:Optional[str] = Field(None, description="Branch for which we are generating release notes against")
 
     def releaseNotesFilename(self, filename:str)->pathlib.Path:
         #Assume that notes are written to dist/. This does not respect build_dir since that is