fix(templates): update issue and MR templates for clarity and cleanup

This MR addresses Issue #15 (closed) by implementing the following improvements to issue_template.md and MR_template.md:

MR_template.md

• Removed the line: “Follows Semantic Versioning” to avoid redundancy and confusion.

issue_template.md

• Removed the "Issue Type" section and replaced it with label usage guidance.
• Corrected the Python version in the Environment Table.
• Removed the "Expected version bump" field (no longer relevant).
• Simplified and clarified checklist items for better readability.