chore: added kb about azure devops

knowledge base/azure devops.md

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+# Azure Devops
+
+## Table of contents <!-- omit in toc -->
+
+1. [Pipelines](#pipelines)
+   1. [Predefined variables](#predefined-variables)
+   1. [Loops](#loops)
+1. [Further readings](#further-readings)
+1. [Sources](#sources)
+
+## Pipelines
+
+### Predefined variables
+
+See [Use predefined variables] for more information.
+
+### Loops
+
+See [Expressions] for more information.
+
+Use the `each` keyword to loop through **parameters of the object type**:
+
+```yaml
+parameters:
+  - name: listOfFruits
+    type: object
+    default:
+      - fruitName: 'apple'
+        colors: ['red','green']
+      - fruitName: 'lemon'
+        colors: ['yellow']
+
+steps:
+  - ${{ each fruit in parameters.listOfFruits }} :
+    - ${{ each fruitColor in fruit.colors}} :
+      - script: echo ${{ fruit.fruitName}} ${{ fruitColor }}
+```
+
+## Further readings
+
+- [Expressions]
+- [Use predefined variables]
+
+## Sources
+
+All the references in the [further readings] section, plus the following:
+
+- [Loops in Azure DevOps Pipelines]
+
+<!-- project's references -->
+[expressions]: https://learn.microsoft.com/en-us/azure/devops/pipelines/process/expressions
+[use predefined variables]: https://learn.microsoft.com/en-us/azure/devops/pipelines/build/variables
+
+<!-- internal references -->
+[further readings]: #further-readings
+
+<!-- external references -->
+[loops in azure devops pipelines]: https://pakstech.com/blog/azure-devops-loops/