Add pipeline for building PCL's environment docker image

.ci/azure-pipelines/env.yml

@@ -10,11 +10,17 @@ trigger:
     include:
     - .dev/docker/env/Dockerfile
 
-pr: none
+pr:
+  branches:
+    include:
+    - master
+  paths:
+    include:
+    - .dev/docker/env/Dockerfile
 
 schedules:
-- cron: "0 0 * * *"
-  displayName: "Daily midnight build"
+- cron: "0 0 0 * *"
+  displayName: "Sunday midnight build"
   branches:
     include:
     - master
@@ -38,24 +44,41 @@ stages:
     strategy:
       matrix:
         Ubuntu 16.04:
+          CUDA_VERSION: 9.2
           UBUNTU_DISTRO: 16.04
+          USE_CUDA: true
+          VTK_VERSION: 6
           tag: 16.04
+        Ubuntu 18.04:
+          CUDA_VERSION: 10.2
+          UBUNTU_DISTRO: 18.04
+          USE_CUDA: true
+          VTK_VERSION: 6
+          tag: 18.04
         Ubuntu 20.04:
+          CUDA_VERSION: 11
           UBUNTU_DISTRO: 20.04
+          VTK_VERSION: 7
+          USE_CUDA: ""
           tag: 20.04
     steps:
     - task: Docker@2
       displayName: "Build docker image: env:$(tag)"
       inputs:
         command: build
-        arguments: --no-cache --build-arg UBUNTU_DISTRO=$(UBUNTU_DISTRO) -t $(dockerHubID)/env:$(tag)
+        arguments: |
+          --no-cache
+          --build-arg UBUNTU_DISTRO=$(UBUNTU_DISTRO)
+          --build-arg VTK_VERSION=$(VTK_VERSION)
+          --build-arg USE_CUDA=true
+          -t $(dockerHubID)/env:$(tag)
         dockerfile: '$(Build.SourcesDirectory)/.dev/docker/env/Dockerfile'
-        tags: |
-          "$(tag)""
+        tags: "$(tag)"
     - task: Docker@2
       displayName: "Push docker image env:$(tag)"
       inputs:
         command: push
         containerRegistry: $(dockerHub)
         repository: $(dockerHubID)/env
         tags: "$(tag)"
+        condition: eq(variables['Build.SourceBranch'], 'refs/heads/master')