CI: Ascent (#3078)

## Summary

Add a CI entry to build Ascent in situ vis.

## Additional background

cc @cyrush

- ECP-WarpX/WarpX#2483
- ECP-WarpX/WarpX#2858
- #3077

.github/workflows/ascent.yml

@@ -0,0 +1,35 @@
+name: 🐧 Ascent
+
+on: [push, pull_request]
+
+concurrency:
+  group: ${{ github.ref }}-${{ github.head_ref }}-insituvis
+  cancel-in-progress: true
+
+jobs:
+  ascent:
+    name: Ascent
+    runs-on: ubuntu-20.04
+    if: github.event.pull_request.draft == false
+    env:
+      CXX: g++
+      CC: gcc
+      CMAKE_PREFIX_PATH: /ascent/install/lib/cmake/
+    container:
+      image: alpinedav/ascent:0.8.0
+    steps:
+    - uses: actions/checkout@v2
+    - name: Configure
+      run: |
+        . /ascent_docker_setup_env.sh
+        cmake -S . -B build          \
+            -DCMAKE_BUILD_TYPE=Debug \
+            -DAMReX_ENABLE_TESTS=ON  \
+            -DAMReX_FORTRAN=OFF      \
+            -DAMReX_PARTICLES=ON     \
+            -DAMReX_ASCENT=ON
+    - name: Build
+      run: |
+        . /ascent_docker_setup_env.sh
+        cmake --build build -j 2
+

.github/workflows/sensei.yml

@@ -32,8 +32,7 @@ jobs:
             -DAMReX_ENABLE_TESTS=ON  \
             -DAMReX_FORTRAN=OFF      \
             -DAMReX_PARTICLES=ON     \
-            -DAMReX_SENSEI=ON        \
-            -DCMAKE_CXX_STANDARD=14
+            -DAMReX_SENSEI=ON
     - name: Build
       run: |
         cd build