Add github action

.github/workflows/Benchmark.yml

@@ -0,0 +1,64 @@
+name: Benchmarks
+on: 
+  pull_request:
+    branches:
+      - main
+    paths:
+      - "KomaMRICore/src/**/*"
+      - "KomaMRICore/ext/**/*"
+      - "KomaMRICore/Project.toml"
+      - "KomaMRIBase/src/**/*"
+      - "KomaMRIBase/Project.toml"
+      - "bench/**/*"
+      - ".buildkite/**/*"
+      - "Project.toml"
+  push:
+    branches:
+      - main
+      - benchmark #TO-DO: remove this
+    paths:
+      - "KomaMRICore/src/**/*"
+      - "KomaMRICore/ext/**/*"
+      - "KomaMRICore/Project.toml"
+      - "KomaMRIBase/src/**/*"
+      - "KomaMRIBase/Project.toml"
+      - "bench/**/*"
+      - ".buildkite/**/*"
+      - "Project.toml"
+
+jobs:
+  benchmark:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download Buildkite Artifacts
+        id: download
+        uses: EnricoMi/download-buildkite-artifact-action@v1
+        with:
+          buildkite_token: ${{ secrets.BUILDKITE_TOKEN }}
+          ignore_build_states: blocked,canceled,skipped,not_run,failed
+          ignore_job_states: timed_out,failed
+          output_path: artifacts
+          log_level: DEBUG #TO-DO: remove this
+          permissions:
+            metadata: read
+            contents: read
+            statuses: read
+
+      - name: Locate Benchmarks Artifact
+        id: locate
+        if: ${{ steps.download.download_state == success}}
+        run: echo "path=$(find artifacts -type f -name combinedbenchmarks.json)" >> $GITHUB_OUTPUT
+
+
+      - name: Upload Benchmark Results
+        if: ${{ steps.download.download_state == success && steps.locate.path != '' }}
+        uses: benchmark-action/github-action-benchmark@v1
+          name: KomaMRI Benchmarks
+          tool: 'julia'
+          output-file-path: ${{ steps.locate.path }}
+          summary-always: true
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          comment-always: true
+          alert-threshold: "150%"
+          fail-on-alert: false
+          auto-push: ${{ github.event_name != 'pull_request' }}