Add tasks for 4 and 8

Author: Wentril

course-E375004.md

@@ -32,7 +32,7 @@
 
    - Notebook a) [tabular data, pandas](courses/E375004/data_pandas/basics_01.ipynb)
    - Notebook b) [COVID data example](courses/E375004/data_pandas/basics_02.ipynb)
-   - task: TBA
+   - task: [here](tasks/EN_pandas_covid_2.ipynb)
    - responsible person: adam.peichl@fs.cvut.cz
 
 5. **Multithreading** 
@@ -57,7 +57,7 @@
 8. **Optimisation - linear programming** - 
 
    - Source codes: [start-here](courses/E375004/optimisation/cvxpy.md)
-   - task: TBA
+   - task: [here](tasks/EN_cvxpy_factory.ipynb)
    - responsible person: adam.peichl@fs.cvut.cz
 
 ## Bonus Lectures