Update README.md

With Homebrew/homebrew-core#13567 script is now installed in a different location. updating README.md to reflect

Author: Vithon

README.md

@@ -23,7 +23,7 @@ Install
 Using the [Homebrew]( https://brew.sh ) package manager:
 
     brew install zsh-history-substring-search
-    echo 'source /usr/local/opt/zsh-history-substring-search/zsh-history-substring-search.zsh' >> ~/.zshrc
+    echo 'source /usr/local/share/zsh-history-substring-search/zsh-history-substring-search.zsh' >> ~/.zshrc
 
 Usage
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