add $10 campaign

README.md

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+## [Get this title for $10 on Packt's Spring Sale](https://www.packt.com/B08516?utm_source=github&utm_medium=packt-github-repo&utm_campaign=spring_10_dollar_2022)
+-----
+For a limited period, all eBooks and Videos are only $10. All the practical content you need \- by developers, for developers
+
 # Computer Vision with OpenCV 3 and Qt5
 This is the code repository for [Computer Vision with OpenCV 3 and Qt5](https://www.packtpub.com/application-development/computer-vision-opencv-3-and-qt5?utm_source=github&utm_medium=repository&utm_campaign=9781788472395), published by [Packt](https://www.packtpub.com/?utm_source=github). It contains all the supporting project files necessary to work through the book from start to finish.
 ## About the Book