Update README and CHANGELOG for v4.0 (#32)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+- `v4.0`
+  - Fix getting company name for different scenarios
+  - feat: Update LinkedIn signature with profile name
+  - Allow separate signatures for messages and connection requests
+  - Improved popup UI with multiple changes
 - `v3.3`
   - Fix: Connection note used to get reset when focus was lost
   - Feature: Added the extension icon to toggle the signature from the message form itself

README.md

@@ -1,6 +1,6 @@
 # SignatureSync
 
-[![Version](https://img.shields.io/badge/Version-3.3-blue.svg)]() [![Release Workflow](https://github.com/prvashisht/signature-sync/actions/workflows/release-extension.yaml/badge.svg?branch=main)](https://github.com/prvashisht/signature-sync/actions/workflows/release-extension.yaml)
+[![Version](https://img.shields.io/badge/Version-4.0-blue.svg)]() [![Release Workflow](https://github.com/prvashisht/signature-sync/actions/workflows/release-extension.yaml/badge.svg?branch=main)](https://github.com/prvashisht/signature-sync/actions/workflows/release-extension.yaml)
 
 SignatureSync is an open-source browser extension designed to enhance your professional messaging experience. Say goodbye to repetitive typing and hello to effortless conversations. SignatureSync allows you to set your signatures once, automatically appending them to your messages, ensuring a polished and professional touch.