fix broken links

Author: joaquinvanschoren

intro.md

@@ -37,11 +37,11 @@ Download the lab notebooks and solve the questions locally, or launch them in Go
 |   | Notebooks          |     Tutorial     |    Solutions   |
 |:--|:-------------------|------------------|----------------|
 | 1 | [Linear Models for regression](https://ml-course.github.io/master/labs/lab-1a-linear-models-for-regression) <br> [Linear Models for classification](https://ml-course.github.io/master/labs/Lab%201b%20-%20Linear%20Models%20for%20Classification) | [Tutorial](https://ml-course.github.io/master/labs/Lab%201%20-%20Tutorial) | [Lab 1a](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%201a%20-%20Linear%20Models%20for%20Regression%20Solution.ipynb) <br> [Lab 1b](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%201b%20-%20Linear%20Models%20for%20Classification%20Solution) (Release date: 4 Feb, 12:00)
-| 2 | [Model Evaluation](https://ml-course.github.io/master/labs/lab-2a-model-evaluation) | [Tutorial](https://ml-course.github.io/master/labs/Lab%202%20-%20Tutorial) | [Lab 2](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%202%20-%20Model%20Evaluation%20Solution) (Release date: 11 Feb, 12:00)
-| 3 | [Ensembles](https://ml-course.github.io/master/labs/lab-3a-ensembles) <br> [Data engineering](https://ml-course.github.io/master/labs/Lab%203b%20-%20Pipelines) | [Tutorial](https://ml-course.github.io/master/labs/Lab%203%20-%20Tutorial) | [Lab 3a](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%203a%20-%20Ensembles%20Solution) <br> [Lab 3b](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%203b%20-%20Pipelines%20Solution) (Release date: 25 Feb, 12:00)
-| 4 | [Neural Networks](https://ml-course.github.io/master/labs/lab-4a-neural-networks)  |  [Tutorial](https://ml-course.github.io/master/labs/Lab%204%20-%20Tutorial) | [Lab 4](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%204%20-%20Neural%20Networks%20Solution) (Release date: 4 Mar, 12:00)
-| 5 | [Convolutional Neural Networks](https://ml-course.github.io/master/labs/lab-5-convolutional-neural-networks)  | / | [Lab 5](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%205%20-%20Convolutional%20Neural%20Networks%20Solution) (Release date: 11 Mar, 12:00)
-| 6 | [Transformers](https://ml-course.github.io/master/labs/lab-6-transformers)<sup>1</sup>  |  [Tutorial](https://ml-course.github.io/master/labs/Lab%206%20-%20Tutorial) | [Lab 6](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%206a%20-%20Transformers%20Solution) (Release date: 18 Mar, 12:00)
+| 2 | [Model Evaluation](https://ml-course.github.io/master/labs/lab-2a-model-evaluation) | [Tutorial](https://ml-course.github.io/master/labs/Lab%202%20-%20Tutorial) | [Lab 2](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%202%20-%20Model%20Evaluation%20Solution.ipynb) (Release date: 11 Feb, 12:00)
+| 3 | [Ensembles](https://ml-course.github.io/master/labs/lab-3a-ensembles) <br> [Data engineering](https://ml-course.github.io/master/labs/Lab%203b%20-%20Pipelines) | [Tutorial](https://ml-course.github.io/master/labs/Lab%203%20-%20Tutorial) | [Lab 3a](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%203a%20-%20Ensembles%20Solution.ipynb) <br> [Lab 3b](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%203b%20-%20Pipelines%20Solution.ipynb) (Release date: 25 Feb, 12:00)
+| 4 | [Neural Networks](https://ml-course.github.io/master/labs/lab-4a-neural-networks)  |  [Tutorial](https://ml-course.github.io/master/labs/Lab%204%20-%20Tutorial) | [Lab 4](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%204%20-%20Neural%20Networks%20Solution.ipynb) (Release date: 4 Mar, 12:00)
+| 5 | [Convolutional Neural Networks](https://ml-course.github.io/master/labs/lab-5-convolutional-neural-networks)  | / | [Lab 5](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%205%20-%20Convolutional%20Neural%20Networks%20Solution.ipynb) (Release date: 11 Mar, 12:00)
+| 6 | [Transformers](https://ml-course.github.io/master/labs/lab-6-transformers)<sup>1</sup>  |  [Tutorial](https://ml-course.github.io/master/labs/Lab%206%20-%20Tutorial) | [Lab 6](https://github.com/ML-course/master/blob/master/lab_solutions/Lab%206a%20-%20Transformers%20Solution.ipynb) (Release date: 18 Mar, 12:00)
 | 6 | [Finetuning Foundation Models]()<sup>1</sup>  |  [Tutorial]() | [Lab 7]() (Release date: 25 Mar, 12:00)
 
 ## Background materials