docs: add Azure Pipelines CI example (#2582)

Co-authored-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

www/docs/ci/azurepipelines.md

@@ -0,0 +1,49 @@
+# Azure Pipelines
+
+Generally there're two ways to define an [Azure Pipeline](https://azure.microsoft.com/en-us/services/devops/pipelines/):
+Classic pipelines defined in the UI or YAML pipelines.
+
+Here is how to do it with YAML:
+
+```yaml
+# customize trigger to your needs
+trigger:
+  branches:
+    include:
+      - main
+      - refs/tags/*
+
+variables:
+  GO_VERSION: "1.17"
+
+pool:
+  vmImage: ubuntu-latest
+
+jobs:
+  - job: Test
+    steps:
+      - task: GoTool@0
+        inputs:
+          version: "$(GO_VERSION)"
+        displayName: Install Go
+
+      - bash: go test ./...
+        displayName: Run Go Tests
+
+  - job: Release
+    # only runs if Test was successful
+    dependsOn: Test
+    # only runs if pipeline was triggered from a branch.
+    condition: and(succeeded(), startsWith(variables['Build.SourceBranch'], 'refs/tags'))
+    steps:
+      - task: GoTool@0
+        inputs:
+          version: "$(GO_VERSION)"
+        displayName: Install Go
+
+      - bash: curl -sL https://git.io/goreleaser | bash
+        displayName: Run Goreleaser
+```
+
+In this example a `Test` job is used to run `go test ./...` to first make sure that there're no failing tests.
+Only if that job succeeds and the pipeline was triggered from a tag (because of the defined `condition`) Goreleaser will be run.