[hp-fetch-merge] Implement hands on T3L3/hp-fetch-merge (#99)

# Exercise Review

## Exercise Discussion

#86 

## Checklist

- [ ] If you require a new remote repository on the `Git-Mastery`
organization, have you [created a
request](https://github.com/git-mastery/exercises/issues/new?template=request_exercise_repository.md)
for it?
- [ ] Have you written unit tests using
[`repo-smith`](https://github.com/git-mastery/repo-smith) to validate
the exercise grading scheme?
- [x] Have you tested the download script using `test-download.sh`?
- [x] Have you verified that this exercise does not already exist or is
not currently in review?
- [ ] Did you introduce a new grading mechanism that should belong to
[`git-autograder`](https://github.com/git-mastery/git-autograder)?
- [ ] Did you introduce a new dependency that should belong to
[`app`](https://github.com/git-mastery/app)?

---------

Co-authored-by: jovnc <95868357+jovnc@users.noreply.github.com>

Author: LeeZeHao

hands_on/fetch_merge.py

@@ -0,0 +1,17 @@
+import os
+
+from exercise_utils.git import add_remote, clone_repo_with_git, remove_remote
+
+__requires_git__ = True
+__requires_github__ = False
+
+
+def download(verbose: bool):
+    clone_repo_with_git(
+        "https://github.com/git-mastery/samplerepo-finances.git", verbose
+    )
+    os.chdir("samplerepo-finances")
+    remove_remote("origin", verbose)
+    add_remote(
+        "origin", "https://github.com/git-mastery/samplerepo-finances-2", verbose
+    )