Add plyer for notifications

[yevdam]

Heavily inspired by PR #3. Adds a notification after a successful commit that works on Windows, Mac, and Linux.

[sourcery-ai]

Sourcery Code Quality Report

✅  Merging this PR will increase code quality in the affected files by 2.22%.

Quality metrics	Before	After	Change
Complexity	0.13 ⭐	0.16 ⭐	0.03 👎
Method Length	34.25 ⭐	34.20 ⭐	-0.05 👍
Working memory	5.47 ⭐	4.68 ⭐	-0.79 👍
Quality	86.62% ⭐	88.84% ⭐	2.22% 👍

Other metrics	Before	After	Change
Lines	23	34	11

Changed files	Quality Before	Quality After	Quality Change
main.py	86.62% ⭐	88.84% ⭐	2.22% 👍

Here are some functions in these files that still need a tune-up:

File	Function	Complexity	Length	Working Memory	Quality	Recommendation

Legend and Explanation

The emojis denote the absolute quality of the code:

• ⭐ excellent
• 🙂 good
• 😞 poor
• ⛔ very poor

The 👍 and 👎 indicate whether the quality has improved or gotten worse with this pull request.

---

Please see our documentation here for details on how these metrics are calculated.

We are actively working on this report - lots more documentation and extra metrics to come!

Help us improve this quality report!