Merge branch 'add-git-training-march-21' into 'develop'

add survey link and next course announcement

See merge request R3/school/courses!99

2021/2021-03-18_basicGitTraining/slides/thanks.md

@@ -43,5 +43,9 @@
 Contact us if you need help:
 <br><br>
 lcsb-r3@uni.lu
+<br><br>
+We'd appreciate feedback: https://is.gd/gitelixir202103
+<br><br>
+Next course: `High-performance scientific computing using Julia on April 22nd, 2021`
 
 </center>
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