feature: tag from ci fetches commits from remote api

src/git_flow/remote/github.py

@@ -1,5 +1,6 @@
 import requests
 from git_flow import GitFlowError
+from git_flow.git import Commit
 from git_flow.remote.base import RemoteAPI
 
 
@@ -42,5 +43,25 @@ class GithubRemoteAPI(RemoteAPI):
         else:
             raise GitFlowError("Ocurrió un error al crear el tag: " + response.text)
 
+    def get_merge_commits(self, merge_commit: str) -> list[Commit]:
+        prs = self.get_json(self.get_endpoint(f"/commits/{merge_commit}/pulls")).json()
+        pr = next((p for p in prs if p.get("merge_commit_sha") == merge_commit), None)
+
+        if not pr:
+            raise GitFlowError(f"No se encontró un PR para el commit {merge_commit}")
+
+        items = self.get_all_pages(self.get_endpoint(f"/pulls/{pr['number']}/commits"), 100)
+
+        # La API los devuelve del más viejo al más nuevo
+        return [
+            Commit(
+                c["sha"][:7],
+                c["commit"]["message"].splitlines()[0],
+                c["commit"]["author"]["email"],
+                len(c["parents"]) > 1,
+            )
+            for c in reversed(items)
+        ]
+
     def get_endpoint(self, resource: str) -> str:
         return f"{GithubRemoteAPI.API_ENDPOINT}/{self.repository}{resource}"