Update README.md

Added the links for opening the repository directly on MATLAB File Exchange and MATLAB Online

Author: Andreas Apostolatos

README.md

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 ## Courseware on Finite Element Methods
+
+[![View Courseware on Finite Element Methods on File Exchange](https://www.mathworks.com/matlabcentral/images/matlab-file-exchange.svg)](https://www.mathworks.com/matlabcentral/fileexchange/125135-courseware-on-finite-element-methods) or [![Open in MATLAB Online](https://www.mathworks.com/images/responsive/global/open-in-matlab-online.svg)](https://matlab.mathworks.com/open/github/v1?repo=MathWorks-Teaching-Resources/Courseware-on-Finite-Element-Methods&project=CoursewareonFiniteElementMethods.prj)
+
+**Curriculum Module**  
+_Created with R2021b. Compatible with R2021b and later releases._  
+
+## Description ##
+
 This courseware on Finite Element Methods addresses standard and advanced Finite Element formulations for shear-deformable lightweight structures of the Timoshenko beam and Reissner-Minldin plate types.\
 \
 Moreover, the interactive courseware uses extensively the [MATLAB®](https://www.mathworks.com/products/matlab.html) Live Editor and the [Symbolic Math Toolbox™](https://www.mathworks.com/products/symbolic.html) for the development and the presentation.\