Updated spm preview path.

Author: ivanvorobei

Assets/Readme/SPM Install Preview.png renamed to Assets/Readme/spm-install-preview.png

@@ -48,7 +48,7 @@ If you like the project, don't forget to `put star ★` and follow me on GitHub:
 
 Ready for use on iOS 11+. Works with Swift 5+. Required Xcode 12.5 and higher.
 
-<img align="right" src="https://github.com/ivanvorobei/SPAlert/blob/main/Assets/Readme/SPM%20Install%20Preview.png" width="520"/>
+<img align="right" src="https://github.com/ivanvorobei/SPAlert/blob/main/Assets/Readme/spm-install-preview.png" width="520"/>
 
 ### Swift Package Manager