CI: don't let Julia nightly break CI; consider it an early warning

Author: tkluck

.github/workflows/CI.yml

@@ -16,27 +16,35 @@ jobs:
   test:
     name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }}
     runs-on: ${{ matrix.os }}
+    continue-on-error: ${{ matrix.experimental }}
     strategy:
       fail-fast: false
       matrix:
         version:
           - "1.6"  # LTS
           - "1.7"
           - "1"    # Latest Release
-          - nightly
         os:
           - ubuntu-latest
           - macOS-latest
           - windows-latest
         arch:
           - x64
           - x86
+        experimental:
+          - false
         exclude:
           # Test 32-bit only on Linux
           - os: macOS-latest
             arch: x86
           - os: windows-latest
             arch: x86
+        include:
+          - os: ubuntu-latest
+            version: nightly
+            arch: x64
+            experimental: true
+
     steps:
       - name: Avoid line ending issues on Windows
         run: git config --global core.autocrlf false