Fix typo -_-

azure-pipelines.yml

@@ -28,7 +28,7 @@ stages:
       displayName: 'Build Xournal++'
     - bash: |
         ctest
-      workingDirectory: ./Build
+      workingDirectory: ./build
       displayName: 'Run tests'
 
 - stage: Release
@@ -36,7 +36,7 @@ stages:
   - job: Linux
     pool:
       vmImage: 'ubuntu-16.04'
-    displayName: 'Test Xournal++ on Linux'
+    displayName: 'Build for Linux'
     steps:
     - bash: |
         sudo apt-get update
@@ -57,6 +57,7 @@ stages:
       x86_64:
         MSYSTEM: MINGW64
         MSYS2_ARCH: x86_64
+    displayName: 'Build for Windows'
     steps:
       - script: |
           choco install msys2 --params="/InstallDir:%CD:~0,2%\msys64 /NoUpdate /NoPath"
@@ -102,6 +103,7 @@ stages:
   - job: macOS
     pool:
       vmImage: 'macOS-10.13'
+    displayName: 'Build for macOS'
     steps:
     - bash: |
         echo !!!TODO!!!