add free flutter and machine learning course links (#7988)

* add flutter and machine learning course links

* change link from http to https

courses/free-courses-en.md

@@ -463,6 +463,7 @@
 * [Flutter Tutorial](https://www.udacity.com/course/build-native-mobile-apps-with-flutter--ud905) - Matt Sullivan, James Williams, Mary Xia (Udacity)
 * [Flutter Tutorial for Beginners](https://www.udemy.com/course/learn-flutter-beginners-course) - Mayuresh Wankhede (Udemy)
 * [Flutter Tutorial for Beginners](https://www.youtube.com/playlist?list=PL4cUxeGkcC9jLYyp2Aoh6hcWuxFDX6PBJ) - The Net Ninja
+* [Free Flutter Animations Course](https://youtube.com/playlist?list=PL4cUxeGkcC9gP1qg8yj-Jokef29VRCLt1) - The Net Ninja
 * [Free Flutter Course](https://www.youtube.com/playlist?list=PL6yRaaP0WPkVtoeNIGqILtRAgd3h2CNpT) - Vandad Nahavandipoor (YouTube)
 
 
@@ -851,6 +852,7 @@
 * [PyTorch tutorials](https://pytorch.org/tutorials) - PyTorch.org
 * [Stanford SEE 229 - Machine Learning](https://see.stanford.edu/Course/CS229)
 * [Stanford University Machine Learning](https://www.coursera.org/learn/machine-learning)
+* [Understand Machine Learning Engineering by Building Projects](https://github.com/alexeygrigorev/mlbookcamp-code/tree/master/course-zoomcamp) - Alexey Grigorev
 
 
 ### Markdown