Skip duplicate CI tests and cancel concurrent tests (#147)

Author: jishnub

.github/workflows/ci.yml

@@ -14,8 +14,24 @@ on:
       - 'LICENSE.md'
       - 'README.md'
       - '.github/workflows/TagBot.yml'
+
+concurrency:
+  group: build-${{ github.event.pull_request.number || github.ref }}-${{ github.workflow }}
+  cancel-in-progress: true
+
 jobs:
+  pre_job:
+    # continue-on-error: true # Uncomment once integration is finished
+    runs-on: ubuntu-latest
+    # Map a step output to a job output
+    outputs:
+      should_skip: ${{ steps.skip_check.outputs.should_skip }}
+    steps:
+      - id: skip_check
+        uses: fkirc/skip-duplicate-actions@v5
   test:
+    needs: pre_job
+    if: needs.pre_job.outputs.should_skip != 'true'
     name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ github.event_name }}
     runs-on: ${{ matrix.os }}
     strategy: